scholarly journals Gonadotrophin storage patterns in the ewe during the oestrous cycle or after long-term treatment with a GnRH agonist

1998 ◽  
Vol 156 (1) ◽  
pp. 149-157 ◽  
Author(s):  
C Taragnat ◽  
A Bernier ◽  
J Fontaine
Keyword(s):  
Pituitary Gland ◽  
Gnrh Agonist ◽  
Term Treatment ◽  
Oestrous Cycle ◽  
Pituitary Cells ◽  
Double Immunostaining ◽  
Gonadotrophin Secretion ◽  
Long Term Treatment ◽  
Lh Cells

The storage pattern of gonadotrophins in the ewe pituitary was investigated during the oestrous cycle and after desensitization to GnRH using long-term treatment with a GnRH agonist, buserelin. Oestrous cycles in ewes were synchronized with progestagen sponges. Animals were allocated to two experiments. In the first, ewes were killed 36 h (before the preovulatory surge, n = 4), 48 h (end of the preovulatory surge, n = 5), 72 h (post-ovulation, n = 4) and 240 h (luteal phase, n = 3) after sponge removal. In the second experiment, another progestagen sponge was inserted in ewes 84 h after removal of the first sponge. Four ewes were infused continuously with buserelin (50 micrograms/day) for 15 days before killing. A further four ewes received no buserelin (controls). Pituitaries were collected and processed for immunocytochemistry to detect monohormonal (LH or FSH) and multihormonal (LH/FSH) cells. The percentages of LH or FSH immunoreactive cells in the pituitary were lower at the end of the preovulatory surge (7.4 +/- 0.3% and 1.2 +/- 0.3% respectively) compared with the other stages (11.4 +/- 0.5% and 5.4 +/- 0.7% respectively). Analysis of dual immunostaining showed the existence of monohormonal cells for LH and multihormonal cells (LH/FSH). No monohormonal cell for FSH was detected except at the end of the preovulatory surge when a few monohormonal FSH cells appeared (0.1 +/- 0.01% of pituitary cells). The percentage of monohormonal LH cells in the pituitary gland was similar in all studied stages of the oestrous cycle, whereas the percentage of multihormonal cells was lower at the end of the surge. In agonist-treated ewes, the percentages of LH or FSH immunoreactive cells (5.3 +/- 0.5% and 1.5 +/- 0.8% respectively) were decreased compared with controls (9.4 +/- 1% and 7.5 +/- 1.1% respectively). Analysis of the double immunostaining revealed a few monohormonal FSH cells (0.2 +/- 0.01% of pituitary cells) in agonist-treated ewes but not in controls. The percentage of monohormonal LH cells in the pituitary gland increased from 1.9 +/- 0.2% in controls to 3.8 +/- 0.3% in agonist-treated ewes, whereas multihormonal cells dropped from 7.5 +/- 1.1% to 1.3 +/- 0.7%. Our data suggest, therefore, that multihormonal cells contribute to gonadotrophin secretion, either during the preovulatory surge of the oestrous cycle or during the 'flare-up' effect initially induced by a GnRH agonist. Moreover, the appearance of monohormonal FSH cells in some conditions reflects a differential regulation of LH and FSH.

scholarly journals Final height in central precocious puberty after long term treatment with a slow release GnRH agonist.

1996 ◽  
Vol 75 (4) ◽  
pp. 292-297 ◽  
Author(s):  
W Oostdijk ◽  
B Rikken ◽  
S Schreuder ◽  
B Otten ◽  
R Odink ◽  
...  
Keyword(s):  
Precocious Puberty ◽  
Gnrh Agonist ◽  
Slow Release ◽  
Final Height ◽  
Central Precocious Puberty ◽  
Term Treatment ◽  
Long Term Treatment

scholarly journals Long-Term Treatment of Anterior Pituitary Cells with Nitric Oxide Induces Programmed Cell Death

Endocrinology ◽  
2004 ◽  
Vol 145 (4) ◽  
pp. 2064-2070 ◽  
Author(s):  
Miguel Omar Velardez ◽  
Ariel Hernán Poliandri ◽  
Jimena Paula Cabilla ◽  
Cristian Carlos Armando Bodo ◽  
Leticia Inés Machiavelli ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Cell Death ◽  
Programmed Cell Death ◽  
Anterior Pituitary ◽  
Term Treatment ◽  
Pituitary Cells ◽  
Anterior Pituitary Cells ◽  
Long Term Treatment

EFFECTS OF TREATMENT WITH ADRENOCORTICOTROPHIN ON THE HYPOTHALAMO-PITUITARY-ADRENAL SYSTEM

1981 ◽  
Vol 88 (1) ◽  
pp. 131-139 ◽  
Author(s):  
E. STARK ◽  
M. KÄRTESZI ◽  
GY. RAPPAY ◽  
G. B. MAKARA
Keyword(s):  
Electrical Stimulation ◽  
Pituitary Gland ◽  
Term Treatment ◽  
Induced Response ◽  
Medial Basal Hypothalamus ◽  
Long Term Treatment ◽  
Adrenalectomized Rats ◽  
Stimulation Of

Long-term treatment with adrenocorticotrophin (ACTH) inhibited the stress-induced response of the hypophysial-adrenocortical system 24 h after the final ACTH injection. The mechanism of this phenomenon was studied in both normal and adrenalectomized rats, the latter receiving corticosterone at various doses. The effect of electrical stimulation of the medial basal hypothalamus on the concentration of corticosterone in plasma (an indicator of ACTH secretion), the corticotrophin releasing factor (CRF) content of the stalk median eminence (SME), the ACTH content of the pituitary gland and the in-vitro release of ACTH by the pituitary gland incubated with or without addition of SME extract were investigated. Electrical stimulation of the medial basal hypothalamus failed to induce a rise in concentrations of corticosterone in plasma of normal rats treated with ACTH; moreover the levels of hypothalamic CRF and hypophysial ACTH were significantly decreased. Hemipituitary glands of ACTH-treated rats released markedly less ACTH in vitro in response to SME extract than did the control glands. This indicated that long-term hormone administration caused a serious impairment of the responsiveness of the corticotrophic cells toward CRF. Pituitary ACTH content and in-vitro responsiveness of pituitary glands obtained from ACTH-treated, adrenalectomized rats receiving corticosterone replacement seemed to be dependent on the amount of exogenous corticosteroid, but not on that of exogenous ACTH. Our previous and present findings suggest that long-term treatment with ACTH elicits repeatedly increased secretion of endogenous corticosterone, impairing the stress-induced CRF–ACTH release at both the hypothalamic and hypophysial levels. Our data challenge the view that ACTH itself is able to inhibit its own secretion.

scholarly journals Gonadotropin-Releasing Hormone Agonist Treatment in Postmenopausal Women with Hyperandrogenism of Ovarian Origin

2011 ◽  
Vol 96 (5) ◽  
pp. 1197-1201 ◽  
Author(s):  
Esther S. Vollaard ◽  
André P. van Beek ◽  
Frederik A. J. Verburg ◽  
Annemieke Roos ◽  
Jolande A. Land
Keyword(s):  
Postmenopausal Women ◽  
Gnrh Agonist ◽  
Case Series ◽  
Term Treatment ◽  
Benign Tumors ◽  
Gnrh Agonists ◽  
Bilateral Oophorectomy ◽  
Increased Risk ◽  
Long Term Treatment

Context: The most frequent cause of virilization in postmenopausal women is excessive androgen production of ovarian origin. Bilateral oophorectomy is usually performed, even in cases of benign tumors or hyperthecosis. This is the first report of a case series of long-term GnRH-agonist treatment of hyperandrogenism in postmenopausal women. Objective: We present three women with postmenopausal hyperandrogenism of ovarian origin who were treated with GnRH agonists. Patients: We describe three cases of postmenopausal women with virilization and hyperandrogenism of presumed ovarian origin, all with slight enlargement of the ovaries but without visualization of a tumor, who had long-term treatment with GnRH agonists. No histological diagnosis was available, and therefore all patients received careful follow-up, including periodic testing of androgen levels and ovarian imaging by computed tomography scans. The three patients responded in different ways to treatment with GnRH agonists. Conclusions: Long-term GnRH agonist treatment is an acceptable choice for treatment of postmenopausal hyperandrogenism in patients where ovarian origin of androgen excess is ascertained, and especially in those patients who have an increased risk for surgery due to comorbidities or who are unwilling to undergo bilateral oophorectomy.

scholarly journals Long-term effects of deslorelin implants on reproduction in the female tammar wallaby (Macropus eugenii)

Reproduction ◽  
2005 ◽  
Vol 129 (3) ◽  
pp. 361-369 ◽  
Author(s):  
C A Herbert ◽  
T E Trigg ◽  
M B Renfree ◽  
G Shaw ◽  
D C Eckery ◽  
...  
Keyword(s):  
Gnrh Agonist ◽  
Slow Release ◽  
Tammar Wallaby ◽  
Term Treatment ◽  
Long Term Effects ◽  
Macropus Eugenii ◽  
Reproductive Management ◽  
Long Term Treatment ◽  
Negative Side Effects

The contraceptive and endocrine effects of long-term treatment with implants containing the GnRH agonist deslorelin were investigated in female tammar wallabies (Macropus eugenii). Fertility was successfully inhibited for 515 ± 87 days after treatment with a 5 mg deslorelin implant (n= 7), while control animals gave birth to their first young 159 ± 47 days after placebo implant administration (n= 8). The duration of contraception was highly variable, ranging from 344 to 761 days. The strict reproductive seasonality in the tammar wallaby was maintained once the implant had expired. This inhibition of reproduction was associated with a significant reduction in basal LH concentrations and a cessation of oestrous cycles, as evidenced by low progesterone concentrations. There was evidence to suggest that some aspect of either blastocyst survival, luteal reactivation, pregnancy or birth may be affected by deslorelin treatment in some animals. These results show that long-term inhibition of fertility in the female tammar wallaby is possible using slow-release deslorelin implants. The effects of deslorelin treatment were fully reversible and there was no evidence of negative side effects. Slow-release GnRH agonist implants may represent a practicable method for reproductive management of captive and semi-wild populations of marsupials.

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