Changes in Erythrosinophils of the Anterior Lobe of the Adenohypophysis During Sexual Development and After Copulation in the Male Mongolian Gerbil (original) (raw)
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Common and specific effects of the two major forms of prolactin in the rat testis
AJP: Endocrinology and Metabolism, 2007
Prolactin (PRL) has both stimulatory and inhibitory effects on testicular function, a finding we hypothesized may be related in some part to the form of the hormone present or administered. In the analysis of the pituitary secretion profiles of early pubescent vs. mature male rats, we found PRL released from early pubescent pituitaries had about twice the degree of phosphorylation. Treatment of mature males with either unmodified PRL (U-PRL) or phosphorylated PRL (via the molecular mimic S179D PRL) for a period of 4 wk (circulating level of ∼50 ng/ml) showed serum testosterone decreased by ∼35% only by treatment with the phospho-mimic S179D PRL. Given the specificity of this effect, it was initially surprising that both forms of PRL decreased testicular expression of 3β-hydroxysteroid dehydrogenase and steroidogenic acute regulatory protein. Both forms also increased expression of the luteinizing hormone receptor, but only S179D PRL increased the ratio of short to long PRL receptors...
Immunohistochemical studies of prolactin binding in sex accessory organs of the male rat
Journal of Histochemistry & Cytochemistry, 1978
Although prolactin is generally associated with lactation in the female, target organs for prolactin may also exist in the male. This paper surveys work from our laboratory in which we have used light microscopic immunohistochemistry to test for and to localize prolactin binding sites in sex accessory organs of the male rat. Rehydrated-Bouins' fixed (5 sm) tissue sections were first exposed to vehicle or varying concentrations of highly purified NIAMDD rat prolactin and then to NIAMDD rabbit anti-rat prolactin (APRL) followed by an immunoperoxidase staining sequence. To test for immunospecificity of staining, prolactin-treated sections were also reacted with absorbed APRL (APRL neutralized by mixture with prolactin) instead of APRL In our initial experiments we observed that prolactin preincubation produced dose-dependent, immunospecific staining in the Golgi region of ventral prostate epithelial cells. This staining was indicative of intracellular prolactin binding sites (IPBS). IPBS of rat ventral prostate appeared to be androgen-dependent disappearing after orchidectomy and returning with androgen replacement. More recently we have studied other sex organs of the male rat. In epithelial cells of dorsolateral prostate IPBS were diffuse being found either apically or throughout the cytoplasm. Extracellular prolactin binding activity was also found within the lumina of dorsolateral prostate
Prolactin Actions in the Sheep Testis: A Test of the Priming Hypothesis
Biology of Reproduction, 2001
This study investigated whether prolactin (PRL) plays a priming role in the testis during the nonmating season and thereby facilitates gonadal reactivation. Sexually inactive Soay rams under long days were treated as follows: 1) group C (control) received vehicle, 2) group B received bromocriptine to suppress PRL secretion, 3) group B ؉ PRL received bromocriptine ؉ ovine PRL to reinstate physiological levels of PRL (n ؍ 5/group). Treatments were for 10 wk. The photoperiod was then switched to short days to reactivate the reproductive axis. Testis diameter and sex skin coloration were recorded, and routine blood samples were collected to measure concentrations of FSH, inhibin A, and testosterone (T). At the end of the treatments, blood samples were collected every 10 min for 10 h to monitor LH pulses and the Tresponse to exogenous LH, and a testis biopsy was collected to assess spermatogenic activity (bromodeoxyuridine [BrDU] method) and expression of PRL receptor (reverse transcription-polymerase chain reaction and immunocytochemistry). There were no significant differences between groups in spermatogenesis (BrDU index) or steroidogenesis (T-response), and no difference in the time taken to achieve full testicular redevelopment under short days. Testis diameter and inhibin A were marginally increased in group B ؉ PRL. Overall, this thorough experiment provides minimal support for the priming hypothesis.
International Journal of Biological, Biomolecular, Agricultural, Food and Biotechnological Engineering , 2014
Male factor infertility due to endocrine disturbances such as abnormalities in prolactin levels are encountered in a significant proportion. This case control study was carried out to determine the effects of prolactin on the male reproductive tract, using 200 male white rats. The rats were maintained as the control group (G1), hypoprolactinaemic group (G2), 3 hyperprolactinaemic groups induced using oral largactil (G3), low dose fluphenazine (G4) and high dose fluphenazine (G5). After 100 days, rats were subjected to serum prolactin (PRL) level measurements and for basic seminal fluid analysis (BSA). The difference between serum PRL concentrations of rats in G2, G3, G4 and G5 as compared to the control group were highly significant by Student’s t-test (p<0.001). There were statistically significant differences in seminal fluid characteristics of rats with induced prolactin abnormalities when compared with those of control group (p value <0.05), effects were more marked as the PRL levels rise.
The Anatomical Record, 1984
Near-adjacent, midsagital sections of pituitaries of infantile and adult male Mongolian gerbils in several experimental groups (bachelor, paired, tartaric acid-injected, postcopulatory gerbil, and postcopulatory animal injected with 2-bromo-α-ergocryptine [CB-154]), were stained by a modification of Herlant's tetrachrome and by the peroxidase-labeled antibody method for prolactin. Cell counts of erythrosinophils and cells immunoreactive for prolactin were made. Sequential staining procedures and thin adjacent sections were used to correlate the staining results.Erythrosinophils were very rare in the infant pituitaries; they increased (P < .01) in numbers in bachelaor pituitaries, remained at the same level (P > .05) in paired animals, increased (P < .01) in the postcopulatory gerbils that were injected with tartaric acid, and increased much less (P < .05) in postcopulatory males that were injected with CB-154.Prolactin cells were present in modest numbers in infant pituitaries; they increased (P < .01); in bachelors and reached their highest number in paired animals (P < .001); they remained unchanged (P > .05) in tartaric acid-injected postcopulatory animals but declined (P < .001) in CB-154-injected, postcopulatory animals. The number of prolactin cells was always significantly greater (P < .001) than the number of erythrosinophils.Correlative studies revealed the erythrosinophils, some of the light blue cells, and some of the chromophobes gave positive immunocytochemical reactions for prolactin.Apparently, CB-154 inhibited the erythrosinophils and the immunoreactive prolactin cells in the postcopulatory male gerbil, as indicated by a reduction in the number, size, and staining intensity of the cells.
Hormonal regulation of testicular prolactin receptors and testosterone synthesis in golden hamsters
Biology of Reproduction, 1990
A study was conducted with hypophysectomized hamsters to determine effects of administration of prolactin (PRL), luteinizing hormone (LH), and follicle-stimulating hormone (FSH)-alone or in combination-on testicular PRL receptors and in vitro testosterone production. Hormonal injections commenced the second day after hypophysectomy, and hamsters were killed on Day 5, approximately 13 h after the last hormonal injection. PRL receptor numbers were reduced by hypophysectomy, and PRL administration alone lessened the extent of this decrease. By themselves, neither LH nor FSH affected PIlL receptors, but a combination of PIlL + FSH + LII produced the greatest effect on these receptors. Receptor affinity was only modestly affected by any treatments. In vitro testosterone synthesis was measured after addition of 0, 2, 10, and 50 mIU of human chorionic gonadotropin (hCG) to incubations of testicular tissue. Neither PRL nor FSH by themselves in vivo affected basal or hCG-stimulated testosterone production. However, PIlL + FSH increased (p < 0.05) the magnitude of the in vitro testosterone response to hCG, as well as the sensitivity of that response (slope of the dose-response curve). LII alone increased both basal and trophic effect of LH and FSH. The data also indicate that PRL by itself is incapable of supporting steroidogenesis in the absence of either LII or FSH.
Reproductive Biology and Endocrinology, 2021
Background: The male and female prostates are controlled by steroid hormones, suffering important morphological and physiological changes after castration. Prolactin is involved in the regulation of the male prostate, having already been identified in the tissue, acting through its receptor PRLR. In the Mongolian gerbil, in addition to the male prostate, the female prostate is also well developed and active in its secretion processes. The aim of the present study was to evaluate the effects of exposure to exogenous prolactin in the prostate of both intact and castrated male and female gerbils in order to establish if prolactin administration can sustain prostate cell activity in conditions of sexual hormone deprivation. Methods: The morphological analyses were performed by biometric analysis, lesion histological analysis and morphometric-stereological aspects. In addition, immune-cytochemical tests were performed for prolactin and its receptor, as well as for the receptors of androgen and oestrogen and serum prolactin dosage. All data were submitted to ANOVA or Kruskal-Wallis tests for comparison between groups. P < 0.05 was considered to be statistically significant. Results: The results showed a strong influence of prolactin on the morphology of the prostate, with the development of important epithelial alterations, after only 3 days of administration, and an expressive epithelial cell discard process after 30 days of administration. Prolactin acts in synergy with testosterone in males and mainly with oestrogens in females, establishing different steroid hormonal receptor immunoreactivity according to sex. It was also demonstrated that prolactin can assist in the recovery from some atrophic effects caused in the gland after castration, without causing additional tissue damage. Conclusions: The prolactin and its receptor are involved in the maintenance of the homeostasis of male and female gerbils, and also cause distinct histological alterations after exogenous exposure for 3 and 30 days. The effects of prolactin are related to its joint action on androgens and oestrogens and it can also assist in the recovery from the atrophic effects of castration.
Prostate response to prolactin in sexually active male rats
Reproductive biology and endocrinology : RB&E, 2006
The prostate is a key gland in the sexual physiology of male mammals. Its sensitivity to steroid hormones is widely known, but its response to prolactin is still poorly known. Previous studies have shown a correlation between sexual behaviour, prolactin release and prostate physiology. Thus, here we used the sexual behaviour of male rats as a model for studying this correlation. Hence, we developed experimental paradigms to determine the influence of prolactin on sexual behaviour and prostate organization of male rats. In addition to sexual behaviour recordings, we developed the ELISA procedure to quantify the serum level of prolactin, and the hematoxilin-eosin technique for analysis of the histological organization of the prostate. Also, different experimental manipulations were carried out; they included pituitary grafts, and haloperidol and ovine prolactin treatments. Data were analyzed with a One way ANOVA followed by post hoc Dunnet test if required. Data showed that male prola...
Prolactin Release in Golden Hamsters: Photoperiod and Gonadal Influences1
Biology of Reproduction, 1981
Serum prolactin (PRL) in male golden hamsters was determined under a variety of experimental conditions. The pattern of daily PRL release appears to be only slightly altered by mild stress, and serum PRL levels are unaltered by castration. Exposure to short photoperiod induces a marked decline in serum PRL titers. Serum PRL levels remain depressed for 19-21 weeks of short-day treatment and then increase spontaneously. The spontaneous elevation of PRL titer appears to be relatively independent of testicular influence since it occurs at the same time in intact and castrated males, as well as in castrated males bearing testosterone implants. Spontaneous PRL release in intact males bearing testosterone implants was delayed 2 weeks. Changes in serum PRL concentrations may have a role in mediating the inhibition of testis function which occurs during exposure to short photoperiod.