EFFECT OF METHYLERGOBASINE MALEATE ON SERUM GONADOTROPHIN AND PROLACTIN IN HUMANS

1975 ◽  
Vol 79 (4) ◽  
pp. 644-657 ◽  
Author(s):  
F. R. Perez-Lopez ◽  
P. Delvoye ◽  
P. Denayer ◽  
M. L'Hermite ◽  
M. C. Roncero ◽  
...  
Keyword(s):  
Intramuscular Injection ◽  
Post Partum ◽  
Prolactin Secretion ◽  
Serum Prolactin ◽  
Pituitary Cells ◽  
Adult Men ◽  
Specific Effects ◽  
Serum Lh ◽  
Menstruating Women

ABSTRACT Intramuscular injection of 0.2 mg methylergobasine maleate3) (Methergin®, Sandoz) in women on day 3 post-partum, in regularly menstruating women and in adult men, is followed within 30 to 75 min by a 50 % decrease in serum prolactin concentration: the levels remain low until 180 min and increase between 180 and 240 min. The amplitude of the decrease is the same when prolactin is measured in terms of the same serum prolactin standard by a homologous ovine assay and by a homologous human assay. However, in the case of regularly menstruating women and of men serum prolactin concentration is some three times higher when estimated by the ovine assay than when estimated by the human assay. This difference between assay results obtained by the two radioimmunoassay methods could be due to heterogeneity of serum prolactin. However, non-specific effects of serum are not excluded. In regularly menstruating women and in men, intramuscular injection of 0.2 mg methylergobasine maleate is followed within 45 to 75 min by a 50% decrease in immunoreactive serum LH concentration without concomtant change in immunoreactive FSH. The depression of LH secretion lasts for 1 to 2 h. The circulating levels of HCG in post-partum women are not modified after intramuscular injection of Methergin. In humans as in animals and in in vitro studies, inhibition of prolactin and LH release induced by ergot drugs are likely due to both an indirect effect via the hypothalamus and to a direct effect on the pituitary cells. Finally, these data suggest that, because of its interference with prolactin secretion, intensive treatment with ergot drugs during the post-partum period may impair lactation.

Excess in vitro prolactin secretion by pituitary cells from ovariectomized old rats

1984 ◽  
Vol 247 (4) ◽  
pp. E483-E488
Author(s):  
M. Haji ◽  
G. S. Roth ◽  
M. R. Blackman
Keyword(s):  
In Vitro Release ◽  
Prolactin Secretion ◽  
Female Rats ◽  
Ovariectomized Rats ◽  
Serum Prolactin ◽  
Pituitary Cells ◽  
Lh Release ◽  
Old Rats

Various in vivo and in vitro pituitary lactotropic and gonadotropic functions were measured in mature (6-7 mo, normally cycling) and old (24 mo, constant diestrus) female Wistar rats. Serum prolactin (PRL) levels were higher (P less than 0.001), whereas luteinizing hormone (LH) values were similar (P greater than 0.05) in old versus mature rats both before and 3 days after ovariectomy. Serum PRL levels decreased significantly (P less than 0.005) postovariectomy only in the mature rats. The in vitro release of PRL and LH was measured for 4 days in primary adenohypophyseal cell cultures from the ovariectomized rats. Both basal and 17 beta-estradiol (E2)-stimulated PRL release (P less than 0.001) and production (P less than 0.005) were greater by cells from old rats. In contrast, both basal release and E2-stimulated LH release were greater (P less than 0.001) by cells from mature rats. Peak PRL release by cells from both old and mature rats occurred after exposure to E2 doses 1/100th of those required for peak LH release. These data support the hypothesis that intrinsic derangements in anterior pituitary function contribute to the reproductive decline in aging female rats and that different pituitary cell types exhibit discordant age changes in estrogenic sensitivity.

Modulation of prolactin secretion by contraceptive progestins in cultured rat pituitary cells in vitro

1988 ◽  
Vol 117 (4_Suppl) ◽  
pp. S188-S189
Author(s):  
L. KIESEL ◽  
T. RABE ◽  
D. SCHOLZ ◽  
V. KIRSCHNER ◽  
B. RUNNEBAUM
Keyword(s):  
Prolactin Secretion ◽  
Pituitary Cells ◽  
Rat Pituitary ◽  
Rat Pituitary Cells

A COMPARISON OF THE EFFECTS OF FOUR ERGOT DERIVATIVES ON PROLACTIN SECRETION BY DISPERSED RAT PITUITARY CELLS

1980 ◽  
Vol 87 (1) ◽  
pp. 95-103 ◽  
Author(s):  
G. DELITALA ◽  
T. YEO ◽  
ASHLEY GROSSMAN ◽  
N. R. HATHWAY ◽  
G. M. BESSER
Keyword(s):  
Anterior Pituitary ◽  
Ergot Alkaloids ◽  
Prolactin Secretion ◽  
Pituitary Cells ◽  
Inhibitory Effects ◽  
Prolactin Release ◽  
Ergot Derivatives ◽  
Rat Pituitary ◽  
Rat Pituitary Cells

The inhibitory effects of dopamine and various ergot alkaloids on prolactin secretion were studied using continuously perfused columns of dispersed rat anterior pituitary cells. Bromocriptine (5 nmol/l) and lisuride hydrogen maleate (5 nmol/l) both inhibited prolactin secretion, the effects persisting for more than 3 h after the end of the administration of the drugs. A similar although less long-lasting effect was observed with lergotrile (50 nmol/l) and the new ergoline derivative, pergolide (5 nmol/l). These effects contrasted with the rapid disappearance of the action of dopamine. The potency estimates of the ergots relative to that of dopamine were: lergotrile, 2·3; bromocriptine, 13; lisuride, 15; pergolide, 23. The dopamine-receptor blocking drugs, metoclopramide and haloperidol, antagonized the prolactin release-inhibiting activity of the compounds; bromocriptine and lisuride showed the highest resistance to this dopaminergic blockade. The results suggested that the direct effect of the ergot derivatives on dispersed pituitary cells was mediated through dopamine receptors and emphasized the long-lasting action of bromocriptine and lisuride in vitro.

scholarly journals Direct Stimulatory Effects of Oxytocin in Female Rat Gonadotrophs and Somatotrophs In Vitro: Comparison With Lactotrophs

Endocrinology ◽  
2014 ◽  
Vol 156 (2) ◽  
pp. 600-612 ◽  
Author(s):  
Arturo E. Gonzalez-Iglesias ◽  
Patrick A. Fletcher ◽  
José A. Arias-Cristancho ◽  
Ruth Cristancho-Gordo ◽  
Cleyde V. Helena ◽  
...  
Keyword(s):  
Receptor Antagonist ◽  
Cell Types ◽  
Pituitary Hormones ◽  
Prolactin Secretion ◽  
Female Rats ◽  
Pituitary Cells ◽  
Female Rat ◽  
Dependent Manner ◽  
Rat Pituitary Cells

The peptide oxytocin (OT) is secreted by hypothalamic neurons and exerts numerous actions related to reproduction. OT stimulation of prolactin secretion in female rats is important during the estrous cycle, pregnancy, and lactation. Here we report that OT also stimulates transients of intracellular Ca2+ concentration in somatotrophs and gonadotrophs as well as the release of GH and LH in a dose-dependent manner with EC50 values that closely correspond to the ligand affinity of the OT receptor (OTR). Remarkably, the hormone-releasing effect of OT in these two cell types is 2 orders of magnitude more sensitive than that in lactotrophs. The specific OTR agonist [Thr4,Gly7]-oxytocin acutely stimulated the release of LH, GH, and prolactin from female rat pituitary cells in primary culture and increased intracellular Ca2+ concentration in gonadotrophs, somatotrophs, and lactotrophs. In these three cell types, the effects on hormone release and intracellular Ca2+ of both OT and [Thr4,Gly7]oxytocin were abolished by the specific OT receptor antagonist desGly-NH2-d(CH2)5[D-Tyr2,Thr4]OVT but not by the highly selective vasopressin V1a receptor antagonist, d(CH2)5[Tyr(Me)2,Dab5]AVP. Furthermore, 10 nM arginine vasopressin stimulated LH and GH release comparably with a dose of OT that was at least 10 times lower. Finally, the presence of the OTR-like immunoreactivity could be observed in all three cell types. Taken together, these results show that OT directly stimulates gonadotrophs, somatotrophs, and lactotrophs through OT receptors and suggest that OT signaling may serve to coordinate the release of different pituitary hormones during specific physiological conditions.

Inhibitory effects of fumagillin and its analogue TNP-470 on the function, morphology and angiogenesis of an oestrogen-induced prolactinoma in Fischer 344 rats

1996 ◽  
Vol 150 (1) ◽  
pp. 99-106 ◽  
Author(s):  
H Stępień ◽  
M Grochal ◽  
K W Zieliński ◽  
S Mucha ◽  
J Kunert-Radek ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Anterior Pituitary ◽  
Angiogenesis Inhibitors ◽  
Prolactin Secretion ◽  
Prolonged Treatment ◽  
Endothelial Cell Proliferation ◽  
Pituitary Cells ◽  
Fischer 344 ◽  
F344 Rats

Abstract The process of angiogenesis occurs in many physiological states, but it is also essential for the growth of solid tumours and metastasis formation. An abnormal arterial vascularization has been shown in prolactin-secreting pituitary adenomas induced by prolonged treatment with oestrogens in Fischer 344 (F344) rats. It is thought that anti-angiogenic agents might be useful in therapy for these tumours. Fumagillin and its analogue TNP-470 are known to inhibit endothelial cell proliferation selectively, but their effect on lactotroph cell secretory function and prolactinoma formation has not yet been described. The aim of the present study was to examine the effects of fumagillin and TNP-470 on prolactin secretion, and morphological and vascular changes within the anterior pituitary in long-term oestrogen-treated male F344 rats in vivo and in vitro. As expected, 7 weeks after s.c. implantation of Silastic tubes containing 10 mg diethylstilboestrol (DES), a very high rise in serum prolactin levels was found. Both angiogenesis inhibitors injected s.c. at doses of 10 mg/kg body weight for 24 days attenuated the stimulatory effect of DES on prolactin production and release. They also diminished prolactin cell density and inhibited cell proliferation expressed as the number of anterior pituitary cells labelled with bromodeoxyuridine (BrdU), but the effect of TNP-470 was minor compared with fumagillin. Both angioinhibitors suppressed neovascularization within the anterior pituitary with similar potency but, on the other hand, they did not affect DES-induced increases in prolactin secretion from cultured rat pituitary cells and cell proliferation in vitro. In conclusion, our results provide strong evidence for the anti-tumour and anti-prolactin activity of angiogenesis inhibitors in the experimentally oestrogen-induced pituitary adenoma; this might be mediated indirectly through the inhibition of angiogenesis. Journal of Endocrinology (1996) 150, 99–106

scholarly journals Cordycepin Modulate Body Weight by Reducing Prolactin via an Adenosine A1 Receptor

2018 ◽  
Author(s):  
Yuan Li ◽  
Yan Li ◽  
Xueyan Wang ◽  
Hongyue Xu ◽  
Chao Wang ◽  
...  
Keyword(s):  
Body Weight ◽  
Prolactin Secretion ◽  
Adenosine A1 Receptor ◽  
Gh3 Cells ◽  
Serum Prolactin ◽  
Prolactin Release ◽  
Adenosine A1 ◽  
A1 Receptor

Cordycepin is an extract from the insect fungus Cordyceps. militaris, which is a traditional medicine with various biological function. In previous studies, cordycepin had been reported with excellent anti-obesity effect, but the mechanism is unclear. A large quantity of evidences showed that prolactin plays an important part in body weight regulation, hyperprolactinemia can promote appetite and accelerate fat deposition. In this study, we explored the molecular mechanism of the anti-obesity effect of cordycepin by reducing prolactin release via an adenosine A1 receptor. In vivo, obese rats model was induced by high fat diet for 5 weeks, the serum and liver lipids coupling with serum prolactin were reduced by treatment of cordycepin, the results suggested that cordycepin is a potential drug for therapying obesity which could be related with prolactin. In vitro, cordycepin could inhibit prolactin secretion in GH3 cells via upregulating the expression of adenosine A1 receptor, the inhibition effect could be blocked by an antagonist of adenosine receptor A1 DPDPX, prolactin induced the upregulation of lipogenesis genes PRLR, and P-JAK2 in 3T3-L1 cells. Intriguingly, cordycepin would down-regulate the expression of prolactin receptor (PRLR). Thus, we concluded that cordycepin modulate body weight by reducing prolactin release via an adenosine A1 receptor.

scholarly journals Identification, purification, and partial characterization of a factor from rabbit serum that inhibits prolactin secretion by pituitary cells cultured in vitro

IUBMB Life ◽  
1997 ◽  
Vol 42 (6) ◽  
pp. 1199-1213
Author(s):  
Sabrina Giacomelli ◽  
C. Yan Cheng ◽  
Maria Grazia Leone ◽  
Maura Palmery ◽  
Bruno Silvestrini
Keyword(s):  
Prolactin Secretion ◽  
Partial Characterization ◽  
Rabbit Serum ◽  
Pituitary Cells ◽  
Cells Cultured

ONSET OF OESTROGEN-INDUCED PROLACTIN SECRETION AND DNA SYNTHESIS BY THE RAT PITUITARY GLAND

1977 ◽  
Vol 72 (1) ◽  
pp. 35-39 ◽  
Author(s):  
JOAN JACOBI ◽  
H. M. LLOYD ◽  
J. D. MEARES
Keyword(s):  
Dna Synthesis ◽  
Pituitary Gland ◽  
Prolactin Secretion ◽  
Male Rat ◽  
Serum Prolactin ◽  
Rat Pituitary ◽  
The Times ◽  
Pituitary Prolactin

SUMMARY The times of onset of oestrogen-induced prolactin secretion and DNA synthesis were studied in the pituitary gland of the male rat. At intervals from 3 to 96 h after injection of 10 mg diethylstilboestrol dipropionate, serum and pituitary prolactin concentrations were measured by radioimmunoassay and pituitary DNA synthesis by incorporation of [3H]thymidine in vitro. Serum prolactin was raised significantly from 6 h onwards and DNA synthesis was increased from 30 h onwards. Pituitary prolactin concentration began to increase at 30 h. Significant correlations were obtained between serum prolactin and DNA synthesis from 24 to 72 h but not during the period of prolactin secretion from 6 to 24 h.

Lactation and birth spacing in highland New Guinea

1985 ◽  
Vol 17 (S9) ◽  
pp. 159-173 ◽  
Author(s):  
James W. Wood ◽  
Daina Lai ◽  
Patricia L. Johnson ◽  
Kenneth L. Campbell ◽  
Ila A. Maslar
Keyword(s):  
Live Birth ◽  
Post Partum ◽  
New Guinea ◽  
Birth Spacing ◽  
Prolactin Secretion ◽  
Maternal Serum ◽  
Serum Prolactin ◽  
Contraceptive Effect ◽  
Slow Decline ◽  
Over Time

SummaryThe effects of infant suckling patterns on the post-partum resumption of ovulation and on birth-spacing are investigated among the Gainj of highland New Guinea. Based on hormonal evidence, the median duration of lactational anovulation is 20·4 months, accounting for about 75% of the median interval between live birth and next successful conception (i.e. resulting in live birth). Throughout lactation, suckling episodes are short and frequent, the interval changing slowly over time, from 24 minutes in newborns to 80 minutes in 3-year olds. Maternal serum prolactin concentrations decline in parallel with the changes in suckling patterns, approaching the level observed in non-nursing women by about 24 months post-partum. A path analysis indicates that the interval between suckling episodes is the principal determinant of maternal prolactin concentration, with time since parturition affecting prolactin secretion only in so far as it affects suckling frequency. The extremely prolonged contraceptive effect of breast-feeding in this population thus appears to be due to (i) a slow decline in suckling frequency with time since parturition and (ii) absence of a decline over time in hypothalamic–pituitary responsiveness to the suckling stimulus.

Oestrogenic regulation of testicular androgen production during development in the rat

1985 ◽  
Vol 105 (2) ◽  
pp. 211-218 ◽  
Author(s):  
B. A. Keel ◽  
T. O. Abney
Keyword(s):  
Serum Testosterone ◽  
Male Rats ◽  
Serum Prolactin ◽  
Testicular Function ◽  
Intact Male ◽  
Oestrogen Treatment ◽  
Testosterone Production ◽  
Age Related ◽  
Serum Lh

ABSTRACT The influence of age on the sensitivity of the testis to oestrogens was investigated. Intact male rats at 10, 25, 40 and 53 days of age were injected s.c. with vehicle, 5 or 50 μg oestradiol or diethylstilboestrol (DES)/100 g body wt twice daily for 2 days; the animals were killed 12 h after the last injection. Subsequently, the concentrations of testicular androgens and serum LH, prolactin, testosterone and androstanediol (5α-androstane-3α, 17β-diol) were measured. Testicular androgen production was determined in vitro in the presence or absence of human chorionic gonadotrophin (hCG) or dibutyryl cyclic AMP (dbcAMP). Androgens in the serum and testes displayed an age-related alternating pattern with androstanediol being the major androgen produced at 27 days of age. As a result of oestrogen treatment, serum LH concentrations were decreased while serum prolactin was increased. Serum testosterone was decreased by 36–55% in the 12-day-old group and further reduced by 95% of control values by day 55; serum androstanediol was less sensitive to oestrogen suppression. Testicular concentrations of both testosterone and androstanediol exhibited a marked reduction in 12-day-old animals as a result of oestrogen administration. These values were reduced by 85–95% at day 27 and remained suppressed even at 55 days. Basal production of testosterone was unaffected by oestrogen treatment in 12- and 27-day-old animals but was markedly decreased by day 42. Significant suppression of basal production of androstanediol was observed as early as day 12. Oestradiol treatment caused a significant reduction in hCG responsiveness of both androgens at days 12, 42 and 55. Oestrogen administration resulted in a significant (32–59%) decline in dbcAMP-responsive testosterone production in the 42-day group and a further suppression in the 55-day group. A marked inhibition of dbcAMP-stimulated androstanediol production was also observed in the 42- and 55-day groups. Testosterone production in response to dbcAMP was not significantly altered in the 12- and 27-day groups. With few exceptions the effects of oestradiol and DES on testicular function were similar. The data presented here suggest that the inhibitory effects of oestrogens become more pronounced as the animal approaches adulthood, that oestradiol and DES are similarly effective in regulating testicular function at all ages studied and that the production of both testosterone and androstanediol are suppressed by oestrogen administration. J. Endocr. (1985) 105, 211–218

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