Leonard Kapcala - Academia.edu (original) (raw)

Papers by Leonard Kapcala

Brain Research, 1990

Corticotropin-releasing hormone (CRH) and glucocorticoids are major regulators of the hypothalami... more Corticotropin-releasing hormone (CRH) and glucocorticoids are major regulators of the hypothalamic-pituitary-adrenal (HPA) axis controlling secretion of fl-endorphin and other pro-opiomelanocortin (POMC)-derived peptides from pituitary. Although previous work has shown that CRH stimulates secretion offl-endorphin from adult hypothalamic explants, and that glucocorticoids can inhibit basal and stimulated secretion of POMC-derived peptides from pituitary, the role of glucocorticoids on hypothalamic fl-endorphin secretion is not known. Studies were performed to assess the effects of CRH and dexamethasone, a potent glucocorticoid, on secretion of immunoreactive (IR) fl-endorphin from dissociated fetal hypothalamic cell cultures. CRH (10-9-10 6 M) did not stimulate secretion of IR-fl-endorphin from hypothalamic cells which did release IR-fl-endorphin upon potassium-induced depolarization. However, CRH did stimulate IR-fl-endorphin secretion from fetal hypothalamic explants which were similar to hypothalamic tissue from which dissociated hypothalamic cell cultures were derived. Exposure of cells to dexamethasone (10 -6 M) did not inhibit basal nor potassium-stimulated release of IR-fl-endorphin. These results indicate that: (1) dissociated fetal hypothalamic cells in culture do not exhibit a functional CRH receptor coupled to stimulation of IR-fl-endorphin secretion;

Developmental Brain Research, 1992

Relatively little is known about physiological regulators of hypothalamic beta-endorphin (END) se... more Relatively little is known about physiological regulators of hypothalamic beta-endorphin (END) secretion and mechanisms by which they stimulate secretion. We sought to determine whether activation of the cyclic AMP (cAMP) second messenger pathway was involved in stimulating hypothalamic beta-END secretion from dissociated fetal hypothalamic cells in culture. Forskolin (FSK), a direct activator of adenylate cyclase which stimulates cAMP formation, stimulated immunoreactive (IR)-beta-END secretion. Because FSK can also stimulate independent of increased cAMP formation, we studied dibutyryl cAMP and 8-bromo-cAMP, analogues of cAMP, which also stimulated IR-beta-END secretion. From these studies we conclude: (1) activation of the cAMP second messenger system stimulates IR-beta-END secretion from hypothalamic cells and supports the rationale that endogenous regulators which stimulate this pathway could be involved in the physiological regulation of hypothalamic beta-END secretion; (2) coupling between the cAMP second messenger pathway and stimulation of hypothalamic beta-END secretion which is presumably present at maturity (adulthood) originates at early stages of development (fetal life).

Peptides, 1988

Processing of pro-opiomelanocortin (POMC) in brain and pituitary results in various proportions o... more Processing of pro-opiomelanocortin (POMC) in brain and pituitary results in various proportions of multiple peptides appearing as immunoreactive (IR-) ACTH and IR-beta-endorphin. Because it is desirable that molecular profiles of POMC-related peptides reflect in vivo processing and not isolation artifact, inhibition of proteolytic activity during extraction is critical. Although enzyme inhibitors are frequently used during extraction of POMC-related peptides, their benefit or necessity has not been established. To determine the benefit of using enzyme inhibitors for studying molecular profiles of IR-ACTH and IR-beta-endorphin from rat brain and pituitary, chromatographic profiles were compared to assess the effect of each of several enzyme inhibitors. Results suggested that the enzyme inhibitors studied provided no additional benefit in terms of inhibition of extraction proteolysis over that provided by a strong acid and heat inactivation.

Pediatric Neurology, 2003

Zonisamide is an antiepileptic drug developed and first marketed in Japan in 1989. Cases of oligo... more Zonisamide is an antiepileptic drug developed and first marketed in Japan in 1989. Cases of oligohydrosis, characterized by deficient production and secretion of sweat, were reported in children treated with zonisamide in Japan during development and in the postmarketing period. Zonisamide was approved in the United States in March 2000 for adjunctive treatment of partial seizures in adults. Searching the Food and Drug Administration's Adverse Events Reporting System, we identified six domestic cases of zonisamide-associated oligohydrosis and/or fever, all in patients </= 18 years of age. The calculated reporting rate was 13 cases per 10,000 pediatric-years of exposure, approximately 10-fold the reporting rate in Japan. A possible risk factor for the development of oligohydrosis in these cases was pediatric age, leading to exposure to elevated zonisamide blood levels relative to patient size. Although the mechanism for zonisamide-associated oligohydrosis has not been fully elucidated, the drug may mediate its effect on eccrine sweat glands by inhibiting carbonic anhydrase, thereby influencing pH dynamics, hydrogen ion concentration, and available calcium transients. Awareness of zonisamide-associated oligohydrosis may prevent morbidity, especially in the pediatric population.

Neurosurgery, 1989

A 53-year-old man presented with polydipsia, polyuria, lightheadedness on standing, and syncope. ... more A 53-year-old man presented with polydipsia, polyuria, lightheadedness on standing, and syncope. Visual field deficits suggesting left optic tract compression and pituitary dysfunction consisting of diabetes insipidus, hyperprolactinemia, and anterior pituitary insufficiency were diagnosed. On the computed tomography scan, an isodense, ring-enhancing, parasellar mass was localized primarily in the suprasellar region and also extended into the sella. It was believed that the pituitary hormone hypersecretion and hyposecretion were due to hypothalamic dysfunction from the mass which was initially believed to be a craniopharyngioma. At surgery a Rathke's cleft cyst was resected. The unusual presentation of this Rathke's cleft cyst presenting as a hypothalamic lesion is discussed.

Neuropharmacology, 1981

ABSTRACT

Neuroendocrinology, 1983

Immunoreactive adrenocorticotropin (IR-ACTH) is widely distributed throughout the brain. Highest ... more Immunoreactive adrenocorticotropin (IR-ACTH) is widely distributed throughout the brain. Highest concentrations have been localized in the ventral hypothalamus, a recognized site of origin of IR-ACTH containing neuronal cell bodies. To determine whether IR-ACTH arises in other brain sites, we determined the effect on the concentration of IR-ACTH in several regions of rat brain after intracerebroventricular injection of colchicine, an agent that inhibits axoplasmic transport and leads to an accumulation of neuronal secretory products within cell bodies. Three regions (ventral hypothalamus, dorsal hypothalamus, amygdala) showed a significant increase in concentration of IR-ACTH after colchicine, whereas the hippocampus and preoptic area did not. Because neuropeptides, in general, undergo posttranslational processing during axoplasmic transport, it could be predicted that inhibition of transport would lead to a relative increase in 'large', precursor forms of hormone in regions containing cells of origin of neuropeptide tracts. Therefore, the effect of colchicine on the processing of molecular forms of IR-ACTH was also examined. In brain regions showing a significant increase in IR-ACTH after colchicine, the proportion of 'big' ACTH and ACTH1-39 (relative to total IR-ACTH) increased and the proportion of 'small' ACTH (less than 4,500 daltons) declined. In contrast, size distribution of IR-ACTH species in other areas were either the opposite or were unchanged. These studies indicate that in addition to the ventral hypothalamus, IR-ACTH also originates in the dorsal hypothalamus and the amygdala, and that decreased axoplasmic peptide transport is associated with decreased processing of molecular forms.

Neuroendocrinology, 1997

The corticotropin-releasing hormone (CRH) gene contains a perfect palindromic motif in its promot... more The corticotropin-releasing hormone (CRH) gene contains a perfect palindromic motif in its promoter region that allows binding of the cyclic adenosine monophosphate response element binding protein, CREB. Since previous studies suggest that the CRH gene can be activated by cyclic adenosine monophosphate, we determined whether stress and feedback inhibition by glucocorticoids in CRH-producing neurons in the hypothalamic paraventricular nucleus could be mediated by changes in the phosphorylation of CREB. Antisera to CREB and phospho-CREB Ser133 (PCREB), the active phosphorylated form of CREB, were used for immunohistochemical studies on rat brain. In nonstressed animals CREB immunostaining was confined to the nucleus of cells ubiquitously throughout the hypothalamus, while PCREB immunostaining was discretely localized in magnocellular neurons and only a few cells in the medial parvocellular subdivision of the paraventricular nucleus. Ether and handling stress markedly increased the number of PCREB-labeled neurons in the parvocellular subdivision. Double immunolabeling with CRH antiserum revealed that the majority of hypophysiotropic CRH neurons in stressed animals expressed PCREB. Following systemic administration of dexamethasone (100 micrograms/day) for 2.5 days, PCREB immunostaining was completely abolished in parvocellular CRH-producing neurons after ether or handling stress. Dexamethasone had no apparent effect on CREB immunostaining. These results demonstrate that glucocorticoids suppress CREB phosphorylation in hypophysiotropic CRH neurons and suggest that prevention of CREB phosphorylation is a possible mechanism for feedback inhibition of CRH biosynthesis by glucocorticoids.

Journal of Neurosurgery, 2000

The outcome for children with recurrent malignant brain tumors is poor. The majority of patients ... more The outcome for children with recurrent malignant brain tumors is poor. The majority of patients die of progressive disease within months of relapse, and other therapeutic options are needed. The goal of this Phase I study was to evaluate the safety of in vivo suicide gene therapy in 12 children with recurrent, malignant, supratentorial brain tumors. After optimal repeated tumor resection, multiple injections of murine vector-producing cells shedding murine replication-defective retroviral vectors coding the herpes simplex virus thymidine kinase type 1 (HSV-Tk1) gene were made into the rim of the resection cavity. Fourteen days after the vector-producing cells were injected, ganciclovir was administered for 14 days. The retroviral vector that was used only integrated and expressed HSV-Tk1 in proliferating cells, which are killed after a series of metabolic events lead to cell death. The median age of the patients was 11 years (range 2-15 years). Treated brain tumors included seven malignant gliomas, two ependyminomas, and three primitive neuroectodermal tumors. The patients were treated with one of three escalating dose concentrations of vector-producer cells. Four transient central nervous system adverse effects were considered possibly related to the vector-producing cells. In no child did permanent neurological worsening or ventricular irritation develop, and tests for replication-competent retroviruses yielded negative findings. This Phase I study demonstrates that in vivo gene therapy in which a replication-defective retroviral vector in murine vector-producing cells is delivered by brain injections can be performed with satisfactory safety in a select group of children with localized supratentorial brain tumors.

Journal of Endocrinological Investigation, 1984

During a systematic study of women with idiopathic galactorrhea, we observed several patients wit... more During a systematic study of women with idiopathic galactorrhea, we observed several patients with normal random serum prolactin (PRL) levels and normal menses, but abnormal sellar tomograms characteristic of a pituitary adenoma. To test the hypothesis that these women might have intermittent PRL hypersecretion, we studied PRL secretion by sampling blood every half hour for 24 h in 10 patients and for 17.5 h in another, and compared the findings to those of a group of 5 normal women. The mean 24-h PRL of the 10 patients (16.8 +/- 7.8 ng/ml; mean +/- SD) was not significantly different from that of the normal women (13.6 +/- 3.2 ng/ml), and each patient showed a normal sleep-associated PRL increment. Three individuals exhibited an abnormally elevated 24-h PRL (greater than 20 ng/ml). Increased PRL secretion occurred primarily at night or in the afternoon. Thyrotropin releasing hormone (TRH) administration caused normal or exaggerated PRL responses in all patients tested. High resolution CT scanning of two of the hypersecretors suggested a microadenoma in one case. In another case whose PRL was normal over 17.5 h, transsphenoidal surgery, carried out because of the tomographic findings and the symptom of headaches, demonstrated a 5-mm chromophobe adenoma that did not contain PRL by immunohistochemistry. Postoperatively the galactorrhea persisted. We conclude that most women with galactorrhea, normal PRL, normal menses, and abnormal tomograms have normal PRL secretion. However, a minority of patients with this syndrome do demonstrate intermittent PRL hypersecretion. The etiology of intermittent PRL hypersecretion and its relevance to galactorrhea have not been determined.(ABSTRACT TRUNCATED AT 250 WORDS)

Journal of Endocrinological Investigation, 1982

Recently, bromocriptine has been successfully introduced as medical therapy for the pituitary hyp... more Recently, bromocriptine has been successfully introduced as medical therapy for the pituitary hypersecreting syndromes of hyperprolactinemia and acromegaly. Subsequently, an inhibitory effect on ACTH secretion was reported using bromocriptine in Cushing's disease. While most studies have focused on the acute response to bromocriptine, few have investigated the response to chronic therapy with this agent. In this report, we describe a patient with Cushing's disease in whom an acute inhibition of ACTH and cortisol was demonstrated following bromocriptine and in whom the long term administration of bromocriptine as the sole therapy produced a transient beneficial response. Further pharmacologic testing suggested this inhibitory effect on the hypothalamic-pituitary-adrenal axis was mediated through dopaminergic stimulation.

Journal of Endocrinological Investigation, 1989

Although galactorrhea and/or enhanced prolactin (PRL) secretion have been reported with a variety... more Although galactorrhea and/or enhanced prolactin (PRL) secretion have been reported with a variety of thoracic stimuli, the effect of thoracic stimulation on dynamic prolactin secretion is not clear. A 49-year-old woman with ventilatory muscle weakness from polio presented with galactorrhea, and intermittent hyperprolactinemia but regular menses. The galactorrhea was noted following the use of a new, tight fitting cuirass (thoracic apparatus which assists ventilation). To determine if the new, "tight" cuirass elicited enhanced PRL secretion, and to assess more extensively the effect of such thoracic stimulation on PRL secretion, serum PRL was measured during brief and prolonged stimulation, sleep, and pharmacological manipulation of PRL. Basal PRL was normal (less than 25 ng/ml) and increased during brief stimulation (1 hour) with the "tight" (137%) and "loose" cuirass (140%). Although the absolute increments were similar, the "tight" cuirass elicited an earlier PRL peak than the "loose" cuirass and the PRL began to decrease while the "tight" cuirass was still functioning. Several hours of thoracic stimulation resulted in a transient rise in PRL and a fall to normal, prestimulatory levels despite persistent stimulation. During this stimulation, PRL did not rise after sleep nor after insulin-induced hypoglycemia despite normal cortisol and GH increments, but the PRL response after TRH was exaggerated.(ABSTRACT TRUNCATED AT 250 WORDS)

Journal of Clinical Investigation, 1984

tion in a dose-dependent manner and is of similar potency to secretin and carbamylcholine. This e... more tion in a dose-dependent manner and is of similar potency to secretin and carbamylcholine. This effect appears to require the ACTH18-24 region of CLIP and results from stimulus-secretion coupling rather than augmented protein synthesis. We also confirmed the presence of immunoreactive-adrenocorticotropic hormone (IR-ACTH) in rat pancreatic extract using a COOH-terminally directed antibody to ACTHI.39 and demonstrated that this IR-ACTH co-eluted with synthetic CLIP. These findings suggest that CLIP might be an endogenous modulator of pancreatic exocrine function.

The Journal of Clinical Endocrinology & Metabolism, 1980

We report three patients with craniopharyngiomas who had galactorrhea, oligo/amenorrhea, and abno... more We report three patients with craniopharyngiomas who had galactorrhea, oligo/amenorrhea, and abnormal sellar tomograms, clinically suggesting the presence of a prolactinoma. One patient had an intrasellar craniopharyngioma (Rathke's cleft cyst) diagosed during surgical exploration of the pituitary fossa for removal of a suspected prolactinoma, and two had suprasellar caraniopharyngiomas whose presence was suspected on the basis of computed tomography. This finding emphasizes the importance of computed tomography in the evaluation of patients with the clinical presentation of a prolactinoma. In two patients, PRL levels were elevated before surgery and remained elevated after removal of the craniopharyngioma. In the third case, an initially normal serum PRL level became elevated after removal of the tumor.

Developmental Brain Research, 1992

Relatively little is known about physiological regulators of hypothalamic beta-endorphin (END) se... more Relatively little is known about physiological regulators of hypothalamic beta-endorphin (END) secretion and mechanisms by which they stimulate secretion. We sought to determine whether activation of the cyclic AMP (cAMP) second messenger pathway was involved in stimulating hypothalamic beta-END secretion from dissociated fetal hypothalamic cells in culture. Forskolin (FSK), a direct activator of adenylate cyclase which stimulates cAMP formation, stimulated immunoreactive (IR)-beta-END secretion. Because FSK can also stimulate independent of increased cAMP formation, we studied dibutyryl cAMP and 8-bromo-cAMP, analogues of cAMP, which also stimulated IR-beta-END secretion. From these studies we conclude: (1) activation of the cAMP second messenger system stimulates IR-beta-END secretion from hypothalamic cells and supports the rationale that endogenous regulators which stimulate this pathway could be involved in the physiological regulation of hypothalamic beta-END secretion; (2) coupling between the cAMP second messenger pathway and stimulation of hypothalamic beta-END secretion which is presumably present at maturity (adulthood) originates at early stages of development (fetal life).

Brain Research Bulletin, 1992

Relatively little is known about the regulation of secretion of hypothalamic beta-endorphin, the ... more Relatively little is known about the regulation of secretion of hypothalamic beta-endorphin, the potent opioid that is believed to play a variety of physiological roles in brain. Previous work has shown that arginine vasopressin (AVP), which acts in brain primarily via activation of the phosphoinositol (PI) second messenger system, stimulates secretion of hypothalamic beta-endorphin. To test the hypothesis that activators of protein kinase C (PKC), which is activated following PI hydrolysis, stimulates secretion of beta-endorphins from hypothalamus, we studied the separate effects of stimulators of PKC including phorbol ester 12-myristate-13-acetate (PMA) and 1-oleolyl-2-acetyl glycerol (OAG- a diacyl glycerol analogue) on secretion of immunoreactive (IR-) beta-endorphin (measured by RIA) from dissociated fetal rat hypothalamic cell cultures. We also studied AVP and angiotensin II (Ang II), hypothalamic peptides which activate the PI second messenger pathway, and interactions of PMA and forskolin (FSK), an activator of the cyclic AMP/protein kinase A (PKA) pathway. PMA, OAG, AVP, and Ang II stimulated IR-beta-endorphin secretion. The stimulatory effect of both PMA and FSK on IR-beta-endorphin secretion was greater than that of PMA or FSK alone and was essentially additive.(ABSTRACT TRUNCATED AT 250 WORDS)

Molecular Brain Research, 1997

Many in vitro studies show estrogen regulation of the hypothalamic pro-opiomelanocortin (POMC) sy... more Many in vitro studies show estrogen regulation of the hypothalamic pro-opiomelanocortin (POMC) system, including a decrease in hypothalamic POMC mRNA after estradiol treatment. Because such in vivo experiments do not allow one to determine whether peripheral, interacting systems or extra-hypothalamic brain regions are involved in this regulation, we sought to establish whether estrogen acts directly in hypothalamus to decrease POMC mRNA. Using an in vitro approach, we studied effects of estradiol (E2) on POMC/cyclophilin mRNA concentrations (RNAse protection assays) in neuronal cultures derived from day 17 fetal rat hypothalamus. Chemically defined medium was deprived of progesterone for 2 days prior to E2 treatment and for the duration of the study. E2 (10(-13)-10(-9) M) dose-dependently decreased POMC mRNA concentrations during a 2-day treatment. Whereas the lowest dose (10(-13) M) of E2 resulted in a statistically significant 44% decrease in POMC mRNA concentrations relative to control cultures, this inhibitory effect was lost because higher doses (10(-11) and 10(-9) M) did not produce statistically significant decrements (22 and 16%, respectively) in POMC mRNA concentrations. Additional time course studies revealed that this decrease in POMC mRNA can be seen as early as 4 h after E2 (10(-13) M) treatment. We conclude that E2 inhibition of POMC mRNA concentrations in hypothalamic neuronal cultures indicates that this inhibition can occur directly in hypothalamus.

Brain Research, 1996

Although interleukin (IL)-1 beta activates the hypothalamic-pituitary-adrenal (HPA) axis, the mec... more Although interleukin (IL)-1 beta activates the hypothalamic-pituitary-adrenal (HPA) axis, the mechanisms by which peripheral IL-1 beta acutely stimulates adrenocorticotropin (ACTH) secretion are not clear. Recently, the vagus has been implicated in mediating peripheral cytokine signalling of the brain. To investigate a possible central mechanism for peripheral cytokine stimulation of the HPA axis, we tested the hypothesis that the vagus mediates IL-1 beta activation of the HPA axis by an intra-abdominal stimulus. We studied the effect of subdiaphragmatic vagotomy on plasma ACTH stimulation in rats by intraperitoneal (i.p.) IL-1 beta. Adult male Sprague-Dawley rats underwent subdiaphragmatic vagotomy or sham surgery 1 week prior to study. Rats were killed 1 and 2 h after i.p. saline (control) and low- (4 micrograms/kg) and high-dose (20 micrograms/kg) IL-1 beta. Vagotomy markedly attenuated plasma ACTH secretion at 2 h after high-dose IL-1 beta stimulation and abolished plasma ACTH secretion at 2 h after low-dose IL-1 beta stimulation. At 1 h after low-dose IL-1 beta, stimulation of plasma ACTH in vagotomized animals was also markedly diminished compared to sham animals. However, vagotomy did not alter stimulation of plasma corticosterone at 1 or 2 h after low-dose IL-1 beta or at 2 h after high-dose IL-1 beta. In addition, vagotomy did not alter stimulation of plasma ACTH or corticosterone secretion by insulin-induced hypoglycemia. We conclude that: (1) the vagus plays an important role in stimulation of ACTH secretion by intra-abdominal (i.p.) IL-1 beta; (2) stimulation of corticosterone secretion by i.p. IL-1 beta is not altered by vagotomy; and (3) the inhibitory effect of vagotomy on activation of the HPA axis appears to be specific for immune stimulation by cytokines.

Brain Research, 1990

Corticotropin-releasing hormone (CRH) and glucocorticoids are major regulators of the hypothalami... more Corticotropin-releasing hormone (CRH) and glucocorticoids are major regulators of the hypothalamic-pituitary-adrenal (HPA) axis controlling secretion of beta-endorphin and other pro-opiomelanocortin (POMC)-derived peptides from pituitary. Although previous work has shown that CRH stimulates secretion of beta-endorphin from adult hypothalamic explants, and that glucocorticoids can inhibit basal and stimulated secretion of POMC-derived peptides from pituitary, the role of glucocorticoids on hypothalamic beta-endorphin secretion is not known. Studies were performed to assess the effects of CRH and dexamethasone, a potent glucocorticoid, on secretion of immunoreactive (IR) beta-endorphin from dissociated fetal hypothalamic cell cultures. CRH (10(-9)-10(-6) M) did not stimulate secretion of IR-beta-endorphin from hypothalamic cells which did release IR-beta-endorphin upon potassium-induced depolarization. However, CRH did stimulate IR-beta-endorphin secretion from fetal hypothalamic explants which were similar to hypothalamic tissue from which dissociated hypothalamic cell cultures were derived. Exposure of cells to dexamethasone (10(-6) M) did not inhibit basal or potassium-stimulated release of IR-beta-endorphin. These results indicate that: (1) dissociated fetal hypothalamic cells in culture do not exhibit a functional CRH receptor coupled to stimulation of IR-beta-endorphin secretion; (2) exposure of hypothalamic cells to dexamethasone does not inhibit basal nor depolarization-induced release of IR-beta-endorphin; and (3) dissociated fetal hypothalamic cells may have limited utility in elucidating specific regulatory relationships because of in vitro conditions and/or cytoarchitectural relationships.

Brain Research, 1990

Corticotropin-releasing hormone (CRH) and glucocorticoids are major regulators of the hypothalami... more Corticotropin-releasing hormone (CRH) and glucocorticoids are major regulators of the hypothalamic-pituitary-adrenal (HPA) axis controlling secretion of fl-endorphin and other pro-opiomelanocortin (POMC)-derived peptides from pituitary. Although previous work has shown that CRH stimulates secretion offl-endorphin from adult hypothalamic explants, and that glucocorticoids can inhibit basal and stimulated secretion of POMC-derived peptides from pituitary, the role of glucocorticoids on hypothalamic fl-endorphin secretion is not known. Studies were performed to assess the effects of CRH and dexamethasone, a potent glucocorticoid, on secretion of immunoreactive (IR) fl-endorphin from dissociated fetal hypothalamic cell cultures. CRH (10-9-10 6 M) did not stimulate secretion of IR-fl-endorphin from hypothalamic cells which did release IR-fl-endorphin upon potassium-induced depolarization. However, CRH did stimulate IR-fl-endorphin secretion from fetal hypothalamic explants which were similar to hypothalamic tissue from which dissociated hypothalamic cell cultures were derived. Exposure of cells to dexamethasone (10 -6 M) did not inhibit basal nor potassium-stimulated release of IR-fl-endorphin. These results indicate that: (1) dissociated fetal hypothalamic cells in culture do not exhibit a functional CRH receptor coupled to stimulation of IR-fl-endorphin secretion;

Developmental Brain Research, 1992

Relatively little is known about physiological regulators of hypothalamic beta-endorphin (END) se... more Relatively little is known about physiological regulators of hypothalamic beta-endorphin (END) secretion and mechanisms by which they stimulate secretion. We sought to determine whether activation of the cyclic AMP (cAMP) second messenger pathway was involved in stimulating hypothalamic beta-END secretion from dissociated fetal hypothalamic cells in culture. Forskolin (FSK), a direct activator of adenylate cyclase which stimulates cAMP formation, stimulated immunoreactive (IR)-beta-END secretion. Because FSK can also stimulate independent of increased cAMP formation, we studied dibutyryl cAMP and 8-bromo-cAMP, analogues of cAMP, which also stimulated IR-beta-END secretion. From these studies we conclude: (1) activation of the cAMP second messenger system stimulates IR-beta-END secretion from hypothalamic cells and supports the rationale that endogenous regulators which stimulate this pathway could be involved in the physiological regulation of hypothalamic beta-END secretion; (2) coupling between the cAMP second messenger pathway and stimulation of hypothalamic beta-END secretion which is presumably present at maturity (adulthood) originates at early stages of development (fetal life).

Peptides, 1988

Processing of pro-opiomelanocortin (POMC) in brain and pituitary results in various proportions o... more Processing of pro-opiomelanocortin (POMC) in brain and pituitary results in various proportions of multiple peptides appearing as immunoreactive (IR-) ACTH and IR-beta-endorphin. Because it is desirable that molecular profiles of POMC-related peptides reflect in vivo processing and not isolation artifact, inhibition of proteolytic activity during extraction is critical. Although enzyme inhibitors are frequently used during extraction of POMC-related peptides, their benefit or necessity has not been established. To determine the benefit of using enzyme inhibitors for studying molecular profiles of IR-ACTH and IR-beta-endorphin from rat brain and pituitary, chromatographic profiles were compared to assess the effect of each of several enzyme inhibitors. Results suggested that the enzyme inhibitors studied provided no additional benefit in terms of inhibition of extraction proteolysis over that provided by a strong acid and heat inactivation.

Pediatric Neurology, 2003

Zonisamide is an antiepileptic drug developed and first marketed in Japan in 1989. Cases of oligo... more Zonisamide is an antiepileptic drug developed and first marketed in Japan in 1989. Cases of oligohydrosis, characterized by deficient production and secretion of sweat, were reported in children treated with zonisamide in Japan during development and in the postmarketing period. Zonisamide was approved in the United States in March 2000 for adjunctive treatment of partial seizures in adults. Searching the Food and Drug Administration's Adverse Events Reporting System, we identified six domestic cases of zonisamide-associated oligohydrosis and/or fever, all in patients </= 18 years of age. The calculated reporting rate was 13 cases per 10,000 pediatric-years of exposure, approximately 10-fold the reporting rate in Japan. A possible risk factor for the development of oligohydrosis in these cases was pediatric age, leading to exposure to elevated zonisamide blood levels relative to patient size. Although the mechanism for zonisamide-associated oligohydrosis has not been fully elucidated, the drug may mediate its effect on eccrine sweat glands by inhibiting carbonic anhydrase, thereby influencing pH dynamics, hydrogen ion concentration, and available calcium transients. Awareness of zonisamide-associated oligohydrosis may prevent morbidity, especially in the pediatric population.

Neurosurgery, 1989

A 53-year-old man presented with polydipsia, polyuria, lightheadedness on standing, and syncope. ... more A 53-year-old man presented with polydipsia, polyuria, lightheadedness on standing, and syncope. Visual field deficits suggesting left optic tract compression and pituitary dysfunction consisting of diabetes insipidus, hyperprolactinemia, and anterior pituitary insufficiency were diagnosed. On the computed tomography scan, an isodense, ring-enhancing, parasellar mass was localized primarily in the suprasellar region and also extended into the sella. It was believed that the pituitary hormone hypersecretion and hyposecretion were due to hypothalamic dysfunction from the mass which was initially believed to be a craniopharyngioma. At surgery a Rathke's cleft cyst was resected. The unusual presentation of this Rathke's cleft cyst presenting as a hypothalamic lesion is discussed.

Neuropharmacology, 1981

ABSTRACT

Neuroendocrinology, 1983

Immunoreactive adrenocorticotropin (IR-ACTH) is widely distributed throughout the brain. Highest ... more Immunoreactive adrenocorticotropin (IR-ACTH) is widely distributed throughout the brain. Highest concentrations have been localized in the ventral hypothalamus, a recognized site of origin of IR-ACTH containing neuronal cell bodies. To determine whether IR-ACTH arises in other brain sites, we determined the effect on the concentration of IR-ACTH in several regions of rat brain after intracerebroventricular injection of colchicine, an agent that inhibits axoplasmic transport and leads to an accumulation of neuronal secretory products within cell bodies. Three regions (ventral hypothalamus, dorsal hypothalamus, amygdala) showed a significant increase in concentration of IR-ACTH after colchicine, whereas the hippocampus and preoptic area did not. Because neuropeptides, in general, undergo posttranslational processing during axoplasmic transport, it could be predicted that inhibition of transport would lead to a relative increase in 'large', precursor forms of hormone in regions containing cells of origin of neuropeptide tracts. Therefore, the effect of colchicine on the processing of molecular forms of IR-ACTH was also examined. In brain regions showing a significant increase in IR-ACTH after colchicine, the proportion of 'big' ACTH and ACTH1-39 (relative to total IR-ACTH) increased and the proportion of 'small' ACTH (less than 4,500 daltons) declined. In contrast, size distribution of IR-ACTH species in other areas were either the opposite or were unchanged. These studies indicate that in addition to the ventral hypothalamus, IR-ACTH also originates in the dorsal hypothalamus and the amygdala, and that decreased axoplasmic peptide transport is associated with decreased processing of molecular forms.

Neuroendocrinology, 1997

The corticotropin-releasing hormone (CRH) gene contains a perfect palindromic motif in its promot... more The corticotropin-releasing hormone (CRH) gene contains a perfect palindromic motif in its promoter region that allows binding of the cyclic adenosine monophosphate response element binding protein, CREB. Since previous studies suggest that the CRH gene can be activated by cyclic adenosine monophosphate, we determined whether stress and feedback inhibition by glucocorticoids in CRH-producing neurons in the hypothalamic paraventricular nucleus could be mediated by changes in the phosphorylation of CREB. Antisera to CREB and phospho-CREB Ser133 (PCREB), the active phosphorylated form of CREB, were used for immunohistochemical studies on rat brain. In nonstressed animals CREB immunostaining was confined to the nucleus of cells ubiquitously throughout the hypothalamus, while PCREB immunostaining was discretely localized in magnocellular neurons and only a few cells in the medial parvocellular subdivision of the paraventricular nucleus. Ether and handling stress markedly increased the number of PCREB-labeled neurons in the parvocellular subdivision. Double immunolabeling with CRH antiserum revealed that the majority of hypophysiotropic CRH neurons in stressed animals expressed PCREB. Following systemic administration of dexamethasone (100 micrograms/day) for 2.5 days, PCREB immunostaining was completely abolished in parvocellular CRH-producing neurons after ether or handling stress. Dexamethasone had no apparent effect on CREB immunostaining. These results demonstrate that glucocorticoids suppress CREB phosphorylation in hypophysiotropic CRH neurons and suggest that prevention of CREB phosphorylation is a possible mechanism for feedback inhibition of CRH biosynthesis by glucocorticoids.

Journal of Neurosurgery, 2000

The outcome for children with recurrent malignant brain tumors is poor. The majority of patients ... more The outcome for children with recurrent malignant brain tumors is poor. The majority of patients die of progressive disease within months of relapse, and other therapeutic options are needed. The goal of this Phase I study was to evaluate the safety of in vivo suicide gene therapy in 12 children with recurrent, malignant, supratentorial brain tumors. After optimal repeated tumor resection, multiple injections of murine vector-producing cells shedding murine replication-defective retroviral vectors coding the herpes simplex virus thymidine kinase type 1 (HSV-Tk1) gene were made into the rim of the resection cavity. Fourteen days after the vector-producing cells were injected, ganciclovir was administered for 14 days. The retroviral vector that was used only integrated and expressed HSV-Tk1 in proliferating cells, which are killed after a series of metabolic events lead to cell death. The median age of the patients was 11 years (range 2-15 years). Treated brain tumors included seven malignant gliomas, two ependyminomas, and three primitive neuroectodermal tumors. The patients were treated with one of three escalating dose concentrations of vector-producer cells. Four transient central nervous system adverse effects were considered possibly related to the vector-producing cells. In no child did permanent neurological worsening or ventricular irritation develop, and tests for replication-competent retroviruses yielded negative findings. This Phase I study demonstrates that in vivo gene therapy in which a replication-defective retroviral vector in murine vector-producing cells is delivered by brain injections can be performed with satisfactory safety in a select group of children with localized supratentorial brain tumors.

Journal of Endocrinological Investigation, 1984

During a systematic study of women with idiopathic galactorrhea, we observed several patients wit... more During a systematic study of women with idiopathic galactorrhea, we observed several patients with normal random serum prolactin (PRL) levels and normal menses, but abnormal sellar tomograms characteristic of a pituitary adenoma. To test the hypothesis that these women might have intermittent PRL hypersecretion, we studied PRL secretion by sampling blood every half hour for 24 h in 10 patients and for 17.5 h in another, and compared the findings to those of a group of 5 normal women. The mean 24-h PRL of the 10 patients (16.8 +/- 7.8 ng/ml; mean +/- SD) was not significantly different from that of the normal women (13.6 +/- 3.2 ng/ml), and each patient showed a normal sleep-associated PRL increment. Three individuals exhibited an abnormally elevated 24-h PRL (greater than 20 ng/ml). Increased PRL secretion occurred primarily at night or in the afternoon. Thyrotropin releasing hormone (TRH) administration caused normal or exaggerated PRL responses in all patients tested. High resolution CT scanning of two of the hypersecretors suggested a microadenoma in one case. In another case whose PRL was normal over 17.5 h, transsphenoidal surgery, carried out because of the tomographic findings and the symptom of headaches, demonstrated a 5-mm chromophobe adenoma that did not contain PRL by immunohistochemistry. Postoperatively the galactorrhea persisted. We conclude that most women with galactorrhea, normal PRL, normal menses, and abnormal tomograms have normal PRL secretion. However, a minority of patients with this syndrome do demonstrate intermittent PRL hypersecretion. The etiology of intermittent PRL hypersecretion and its relevance to galactorrhea have not been determined.(ABSTRACT TRUNCATED AT 250 WORDS)

Journal of Endocrinological Investigation, 1982

Recently, bromocriptine has been successfully introduced as medical therapy for the pituitary hyp... more Recently, bromocriptine has been successfully introduced as medical therapy for the pituitary hypersecreting syndromes of hyperprolactinemia and acromegaly. Subsequently, an inhibitory effect on ACTH secretion was reported using bromocriptine in Cushing's disease. While most studies have focused on the acute response to bromocriptine, few have investigated the response to chronic therapy with this agent. In this report, we describe a patient with Cushing's disease in whom an acute inhibition of ACTH and cortisol was demonstrated following bromocriptine and in whom the long term administration of bromocriptine as the sole therapy produced a transient beneficial response. Further pharmacologic testing suggested this inhibitory effect on the hypothalamic-pituitary-adrenal axis was mediated through dopaminergic stimulation.

Journal of Endocrinological Investigation, 1989

Although galactorrhea and/or enhanced prolactin (PRL) secretion have been reported with a variety... more Although galactorrhea and/or enhanced prolactin (PRL) secretion have been reported with a variety of thoracic stimuli, the effect of thoracic stimulation on dynamic prolactin secretion is not clear. A 49-year-old woman with ventilatory muscle weakness from polio presented with galactorrhea, and intermittent hyperprolactinemia but regular menses. The galactorrhea was noted following the use of a new, tight fitting cuirass (thoracic apparatus which assists ventilation). To determine if the new, "tight" cuirass elicited enhanced PRL secretion, and to assess more extensively the effect of such thoracic stimulation on PRL secretion, serum PRL was measured during brief and prolonged stimulation, sleep, and pharmacological manipulation of PRL. Basal PRL was normal (less than 25 ng/ml) and increased during brief stimulation (1 hour) with the "tight" (137%) and "loose" cuirass (140%). Although the absolute increments were similar, the "tight" cuirass elicited an earlier PRL peak than the "loose" cuirass and the PRL began to decrease while the "tight" cuirass was still functioning. Several hours of thoracic stimulation resulted in a transient rise in PRL and a fall to normal, prestimulatory levels despite persistent stimulation. During this stimulation, PRL did not rise after sleep nor after insulin-induced hypoglycemia despite normal cortisol and GH increments, but the PRL response after TRH was exaggerated.(ABSTRACT TRUNCATED AT 250 WORDS)

Journal of Clinical Investigation, 1984

tion in a dose-dependent manner and is of similar potency to secretin and carbamylcholine. This e... more tion in a dose-dependent manner and is of similar potency to secretin and carbamylcholine. This effect appears to require the ACTH18-24 region of CLIP and results from stimulus-secretion coupling rather than augmented protein synthesis. We also confirmed the presence of immunoreactive-adrenocorticotropic hormone (IR-ACTH) in rat pancreatic extract using a COOH-terminally directed antibody to ACTHI.39 and demonstrated that this IR-ACTH co-eluted with synthetic CLIP. These findings suggest that CLIP might be an endogenous modulator of pancreatic exocrine function.

The Journal of Clinical Endocrinology & Metabolism, 1980

We report three patients with craniopharyngiomas who had galactorrhea, oligo/amenorrhea, and abno... more We report three patients with craniopharyngiomas who had galactorrhea, oligo/amenorrhea, and abnormal sellar tomograms, clinically suggesting the presence of a prolactinoma. One patient had an intrasellar craniopharyngioma (Rathke's cleft cyst) diagosed during surgical exploration of the pituitary fossa for removal of a suspected prolactinoma, and two had suprasellar caraniopharyngiomas whose presence was suspected on the basis of computed tomography. This finding emphasizes the importance of computed tomography in the evaluation of patients with the clinical presentation of a prolactinoma. In two patients, PRL levels were elevated before surgery and remained elevated after removal of the craniopharyngioma. In the third case, an initially normal serum PRL level became elevated after removal of the tumor.

Developmental Brain Research, 1992

Relatively little is known about physiological regulators of hypothalamic beta-endorphin (END) se... more Relatively little is known about physiological regulators of hypothalamic beta-endorphin (END) secretion and mechanisms by which they stimulate secretion. We sought to determine whether activation of the cyclic AMP (cAMP) second messenger pathway was involved in stimulating hypothalamic beta-END secretion from dissociated fetal hypothalamic cells in culture. Forskolin (FSK), a direct activator of adenylate cyclase which stimulates cAMP formation, stimulated immunoreactive (IR)-beta-END secretion. Because FSK can also stimulate independent of increased cAMP formation, we studied dibutyryl cAMP and 8-bromo-cAMP, analogues of cAMP, which also stimulated IR-beta-END secretion. From these studies we conclude: (1) activation of the cAMP second messenger system stimulates IR-beta-END secretion from hypothalamic cells and supports the rationale that endogenous regulators which stimulate this pathway could be involved in the physiological regulation of hypothalamic beta-END secretion; (2) coupling between the cAMP second messenger pathway and stimulation of hypothalamic beta-END secretion which is presumably present at maturity (adulthood) originates at early stages of development (fetal life).

Brain Research Bulletin, 1992

Relatively little is known about the regulation of secretion of hypothalamic beta-endorphin, the ... more Relatively little is known about the regulation of secretion of hypothalamic beta-endorphin, the potent opioid that is believed to play a variety of physiological roles in brain. Previous work has shown that arginine vasopressin (AVP), which acts in brain primarily via activation of the phosphoinositol (PI) second messenger system, stimulates secretion of hypothalamic beta-endorphin. To test the hypothesis that activators of protein kinase C (PKC), which is activated following PI hydrolysis, stimulates secretion of beta-endorphins from hypothalamus, we studied the separate effects of stimulators of PKC including phorbol ester 12-myristate-13-acetate (PMA) and 1-oleolyl-2-acetyl glycerol (OAG- a diacyl glycerol analogue) on secretion of immunoreactive (IR-) beta-endorphin (measured by RIA) from dissociated fetal rat hypothalamic cell cultures. We also studied AVP and angiotensin II (Ang II), hypothalamic peptides which activate the PI second messenger pathway, and interactions of PMA and forskolin (FSK), an activator of the cyclic AMP/protein kinase A (PKA) pathway. PMA, OAG, AVP, and Ang II stimulated IR-beta-endorphin secretion. The stimulatory effect of both PMA and FSK on IR-beta-endorphin secretion was greater than that of PMA or FSK alone and was essentially additive.(ABSTRACT TRUNCATED AT 250 WORDS)

Molecular Brain Research, 1997

Many in vitro studies show estrogen regulation of the hypothalamic pro-opiomelanocortin (POMC) sy... more Many in vitro studies show estrogen regulation of the hypothalamic pro-opiomelanocortin (POMC) system, including a decrease in hypothalamic POMC mRNA after estradiol treatment. Because such in vivo experiments do not allow one to determine whether peripheral, interacting systems or extra-hypothalamic brain regions are involved in this regulation, we sought to establish whether estrogen acts directly in hypothalamus to decrease POMC mRNA. Using an in vitro approach, we studied effects of estradiol (E2) on POMC/cyclophilin mRNA concentrations (RNAse protection assays) in neuronal cultures derived from day 17 fetal rat hypothalamus. Chemically defined medium was deprived of progesterone for 2 days prior to E2 treatment and for the duration of the study. E2 (10(-13)-10(-9) M) dose-dependently decreased POMC mRNA concentrations during a 2-day treatment. Whereas the lowest dose (10(-13) M) of E2 resulted in a statistically significant 44% decrease in POMC mRNA concentrations relative to control cultures, this inhibitory effect was lost because higher doses (10(-11) and 10(-9) M) did not produce statistically significant decrements (22 and 16%, respectively) in POMC mRNA concentrations. Additional time course studies revealed that this decrease in POMC mRNA can be seen as early as 4 h after E2 (10(-13) M) treatment. We conclude that E2 inhibition of POMC mRNA concentrations in hypothalamic neuronal cultures indicates that this inhibition can occur directly in hypothalamus.

Brain Research, 1996

Although interleukin (IL)-1 beta activates the hypothalamic-pituitary-adrenal (HPA) axis, the mec... more Although interleukin (IL)-1 beta activates the hypothalamic-pituitary-adrenal (HPA) axis, the mechanisms by which peripheral IL-1 beta acutely stimulates adrenocorticotropin (ACTH) secretion are not clear. Recently, the vagus has been implicated in mediating peripheral cytokine signalling of the brain. To investigate a possible central mechanism for peripheral cytokine stimulation of the HPA axis, we tested the hypothesis that the vagus mediates IL-1 beta activation of the HPA axis by an intra-abdominal stimulus. We studied the effect of subdiaphragmatic vagotomy on plasma ACTH stimulation in rats by intraperitoneal (i.p.) IL-1 beta. Adult male Sprague-Dawley rats underwent subdiaphragmatic vagotomy or sham surgery 1 week prior to study. Rats were killed 1 and 2 h after i.p. saline (control) and low- (4 micrograms/kg) and high-dose (20 micrograms/kg) IL-1 beta. Vagotomy markedly attenuated plasma ACTH secretion at 2 h after high-dose IL-1 beta stimulation and abolished plasma ACTH secretion at 2 h after low-dose IL-1 beta stimulation. At 1 h after low-dose IL-1 beta, stimulation of plasma ACTH in vagotomized animals was also markedly diminished compared to sham animals. However, vagotomy did not alter stimulation of plasma corticosterone at 1 or 2 h after low-dose IL-1 beta or at 2 h after high-dose IL-1 beta. In addition, vagotomy did not alter stimulation of plasma ACTH or corticosterone secretion by insulin-induced hypoglycemia. We conclude that: (1) the vagus plays an important role in stimulation of ACTH secretion by intra-abdominal (i.p.) IL-1 beta; (2) stimulation of corticosterone secretion by i.p. IL-1 beta is not altered by vagotomy; and (3) the inhibitory effect of vagotomy on activation of the HPA axis appears to be specific for immune stimulation by cytokines.

Brain Research, 1990

Corticotropin-releasing hormone (CRH) and glucocorticoids are major regulators of the hypothalami... more Corticotropin-releasing hormone (CRH) and glucocorticoids are major regulators of the hypothalamic-pituitary-adrenal (HPA) axis controlling secretion of beta-endorphin and other pro-opiomelanocortin (POMC)-derived peptides from pituitary. Although previous work has shown that CRH stimulates secretion of beta-endorphin from adult hypothalamic explants, and that glucocorticoids can inhibit basal and stimulated secretion of POMC-derived peptides from pituitary, the role of glucocorticoids on hypothalamic beta-endorphin secretion is not known. Studies were performed to assess the effects of CRH and dexamethasone, a potent glucocorticoid, on secretion of immunoreactive (IR) beta-endorphin from dissociated fetal hypothalamic cell cultures. CRH (10(-9)-10(-6) M) did not stimulate secretion of IR-beta-endorphin from hypothalamic cells which did release IR-beta-endorphin upon potassium-induced depolarization. However, CRH did stimulate IR-beta-endorphin secretion from fetal hypothalamic explants which were similar to hypothalamic tissue from which dissociated hypothalamic cell cultures were derived. Exposure of cells to dexamethasone (10(-6) M) did not inhibit basal or potassium-stimulated release of IR-beta-endorphin. These results indicate that: (1) dissociated fetal hypothalamic cells in culture do not exhibit a functional CRH receptor coupled to stimulation of IR-beta-endorphin secretion; (2) exposure of hypothalamic cells to dexamethasone does not inhibit basal nor depolarization-induced release of IR-beta-endorphin; and (3) dissociated fetal hypothalamic cells may have limited utility in elucidating specific regulatory relationships because of in vitro conditions and/or cytoarchitectural relationships.