Pituitary binding of vasopressin is altered by experimental manipulations of the hypothalamo-pituitary-adrenocortical axis in normal as well as homozygous (di/di) Brattleboro rats - PubMed (original) (raw)
Pituitary binding of vasopressin is altered by experimental manipulations of the hypothalamo-pituitary-adrenocortical axis in normal as well as homozygous (di/di) Brattleboro rats
F A Antoni et al. Endocrinology. 1985 Oct.
Abstract
In the present study we report the properties of vasopressin (VP) receptors in the anterior pituitary gland and show that the number of these receptors is markedly affected by adrenalectomy and hypothalamic lesions. VP-binding activity was assayed in particulate fractions of rat anterior pituitary glands using tritium-labeled arginine VP ([3H] AVP) as tracer. In the presence of Mg2+ the radioligand interacted with a single class of high affinity, low capacity binding sites. Magnesium ions modulated the affinity of the receptors but had no effect on binding capacity. Guanine nucleotides decreased the amount of tracer bound in a dose-dependent manner by increasing the dissociation constant (Kd) of the binding reaction by approximately 2-fold. Increasing the concentration of Mg2+ did not prevent this effect. Bilateral adrenalectomy (ADX) decreased pituitary AVP-binding activity: binding fell by 30% 4 h after surgery and declined further to 10% or less of control at 4 days. The decrease in binding was primarily due to a reduction in the number of receptors. Daily administration of corticosterone inhibited the reduction of binding activity at 4 days in a dose-dependent manner. Destruction of hypophyseotropic VP neurons by means of surgical lesioning of the hypothalamic paraventricular nucleus or the medial basal hypothalamus abolished the effect of ADX on pituitary AVP binding at 24 h but only attenuated the degree of receptor loss at 4 days. Furthermore, the lesions themselves caused a significant (approximately 30%) reduction in receptor number 4-7 days after hypothalamic surgery. Adrenalectomy reduced pituitary AVP-binding activity in homozygous (di/di) Brattleboro rats. The extent as well as the time course of the loss of receptor activity resembled that in normal rats. Rat anterior pituitary segments were exposed to synthetic CRF, AVP, or oxytocin (all 10(-7) M) for 4 h in vitro, and [3H] AVP-binding activity was subsequently determined. Both AVP and oxytocin reduced the amount of radioligand bound, while CRF had no effect. These observations allow the following conclusions: Magnesium ions and guanine nucleotides modulate the affinity of pituitary AVP receptors by different mechanisms and have no effect on binding capacity; Pituitary receptors for AVP are regulated by the amount of AVP released by paraventricular nucleus neurons as well as through a mechanism that requires the presence of corticosterone; Homozygous Brattleboro rats may respond to ADX by increased hypothalamic release of an endogenous ligand for pituitary AVP receptors.
Similar articles
- Central nervous system control of pituitary vasopressin receptors: evidence for involvement of multiple factors.
Lutz-Bucher B, Kovacs K, Makara G, Stark E, Koch B. Lutz-Bucher B, et al. Neuroendocrinology. 1986;43(5):618-24. doi: 10.1159/000124590. Neuroendocrinology. 1986. PMID: 3018613 - [Role of the neurohypophysis in psychological stress].
Scantamburlo G, Ansseau M, Legros JJ. Scantamburlo G, et al. Encephale. 2001 May-Jun;27(3):245-59. Encephale. 2001. PMID: 11488255 Review. French. - Regulation of vasopressin V1b receptors in the anterior pituitary gland of the rat.
Aguilera G, Rabadan-Diehl C. Aguilera G, et al. Exp Physiol. 2000 Mar;85 Spec No:19S-26S. doi: 10.1111/j.1469-445x.2000.tb00004.x. Exp Physiol. 2000. PMID: 10795903 Review.
Cited by
- Gender-dependent characteristics of the hypothalamo-corticotrope axis function in glucocorticoid-replete and glucocorticoid-depleted rats.
Chisari AN, Perone MJ, Giovambattista A, Spinedi E. Chisari AN, et al. J Endocrinol Invest. 1998 Dec;21(11):737-43. doi: 10.1007/BF03348038. J Endocrinol Invest. 1998. PMID: 9972672 - Ca2+/calcineurin-inhibited adenylyl cyclase, highly abundant in forebrain regions, is important for learning and memory.
Antoni FA, Palkovits M, Simpson J, Smith SM, Leitch AL, Rosie R, Fink G, Paterson JM. Antoni FA, et al. J Neurosci. 1998 Dec 1;18(23):9650-61. doi: 10.1523/JNEUROSCI.18-23-09650.1998. J Neurosci. 1998. PMID: 9822726 Free PMC article. - Evidence for arginine vasopressin as the primary activator of the HPA axis during adjuvant-induced arthritis.
Chowdrey HS, Larsen PJ, Harbuz MS, Jessop DS, Aguilera G, Eckland DJ, Lightman SL. Chowdrey HS, et al. Br J Pharmacol. 1995 Nov;116(5):2417-24. doi: 10.1111/j.1476-5381.1995.tb15089.x. Br J Pharmacol. 1995. PMID: 8581278 Free PMC article. - Corticotrophin-releasing factor, vasopressin and pro-opiomelanocortin mRNA responses to stress and opiates in the rat.
Lightman SL, Young WS 3rd. Lightman SL, et al. J Physiol. 1988 Sep;403:511-23. doi: 10.1113/jphysiol.1988.sp017261. J Physiol. 1988. PMID: 3267021 Free PMC article. - Effects of adrenalectomy and glucocorticoids on the peptides CRF-41, AVP and oxytocin in rat hypophysial portal blood.
Fink G, Robinson IC, Tannahill LA. Fink G, et al. J Physiol. 1988 Jul;401:329-45. doi: 10.1113/jphysiol.1988.sp017165. J Physiol. 1988. PMID: 2845063 Free PMC article.
MeSH terms
Substances
LinkOut - more resources
Full Text Sources
Miscellaneous