Long-term exposure of hypothalamic explants to melatonin alters the release of gonadotrophin releasing hormone and the density of melatonin binding sites in the pars tuberalis of the male mink (Mustela vison)

1999 ◽  
Vol 26 (1) ◽  
pp. 17-27 ◽  
Author(s):  
S. Messager ◽  
M. Caillol ◽  
L. Martinet
Keyword(s):  
Binding Sites ◽  
Mustela Vison ◽  
Pars Tuberalis ◽  
Releasing Hormone ◽  
Gonadotrophin Releasing Hormone

Suppression of pituitary-testis function in rats treated neonatally with a gonadotrophin-releasing hormone agonist and antagonist: acute and long-term effects

1989 ◽  
Vol 123 (1) ◽  
pp. 83-91 ◽  
Author(s):  
K.-L. Kolho ◽  
I. Huhtaniemi
Keyword(s):  
Body Weight ◽  
Gnrh Agonist ◽  
Gnrh Antagonist ◽  
Long Term Effects ◽  
Adult Rats ◽  
Releasing Hormone ◽  
Serum Lh ◽  
Accessory Sex Organs ◽  
Gonadotrophin Releasing Hormone

ABSTRACT The acute and long-term effects of pituitary-testis suppression with a gonadotrophin-releasing hormone (GnRH) agonist, d-Ser(But)6des-Gly10-GnRH N-ethylamide (buserelin; 0·02, 0·1, 1·0 or 10 mg/kg body weight per day s.c.) or antagonist, N-Ac-d-Nal(2)1,d-p-Cl-Phe2,d-Trp3,d-hArg(Et2)6,d-Ala10-GnRH (RS 68439; 2 mg/kg body weight per day s.c.) were studied in male rats treated on days 1–15 of life. The animals were killed on day 16 (acute effects) or as adults (130–160 days; long-term effects). Acutely, the lowest dose of the agonist decreased pituitary FSH content and testicular LH receptors, but with increasing doses pituitary and serum LH concentrations, intratesticular testosterone content and weights of testes were also suppressed (P< 0·05–0·01). No decrease was found in serum FSH or in weights of accessory sex organs even with the highest dose of the agonist, the latter finding indicating continuing secretion of androgens. The GnRH antagonist treatment suppressed pituitary LH and FSH contents and serum LH (P< 0·05–0·01) but, as with the agonist, serum FSH remained unaltered. Testicular testosterone and testis weights were decreased (P <0·01) but testicular LH receptors remained unchanged. Moreover, the seminal vesicle and ventral prostate weights were reduced, in contrast to the effects of the agonists. Pituitary LH and FSH contents had recovered in all adult rats treated neonatally with agonist and there was no effect on serum LH and testosterone concentrations or on fertility. In contrast, in adult rats treated neonatally with antagonist, weights of testis and accessory sex organs remained decreased (P <0·01–0·05) but hormone secretion from the pituitary and testis had returned to normal except that serum FSH was increased by 80% (P <0·01). Interestingly, 90% of the antagonist-treated animals were infertile. It is concluded that treatment with a GnRH agonist during the neonatal period does not have a chronic effect on pituitary-gonadal function. In contrast, GnRH antagonist treatment neonatally permanently inhibits the development of the testis and accessory sex organs and results in infertility. Interestingly, despite the decline of pituitary FSH neonatally, neither of the GnRH analogues was able to suppress serum FSH values and this differs from the concomitant changes in LH and from the effects of similar treatments in adult rats. Journal of Endocrinology (1989) 123, 83–91

Effect of long-term inhibition of gonadotrophin secretion by the gonadotrophin-releasing hormone agonist, buserelin, on sex steroid secretion and ovarian morphology in polycystic ovary syndrome

1990 ◽  
Vol 125 (2) ◽  
pp. 317-325 ◽  
Author(s):  
A. F. Macleod ◽  
M. J. Wheeler ◽  
P. Gordon ◽  
C. Lowy ◽  
P. H. Sönksen ◽  
...  
Keyword(s):  
Polycystic Ovary Syndrome ◽  
Gnrh Agonist ◽  
Polycystic Ovary ◽  
Normal Subjects ◽  
Sex Hormone Binding Globulin ◽  
Plasma Testosterone ◽  
Ovary Syndrome ◽  
Releasing Hormone ◽  
Gonadotrophin Releasing Hormone

ABSTRACT In order to investigate the effect of long-term suppression of the gonadotrophin axis in polycystic ovary syndrome, eight affected subjects were given s.c. infusions of gonadotrophin-releasing hormone (GnRH) agonist buserelin for 12 weeks. Hormone measurement and ultrasound studies were carried out weekly, from 6 weeks before to 12 weeks after administration of buserelin. An overnight dexamethasone-suppression test was carried out before and after treatment. Maximal suppression of LH to below the lower limit of that in normal subjects occurred after 6 weeks of treatment with buserelin. Plasma testosterone and androstenedione fell to normal levels during the infusion but reached pretreatment levels during the follow-up period. There was no effect of buserelin on plasma dehydroepiandrosterone sulphate or sex hormone-binding globulin. Ovarian size decreased significantly during the infusion with the disappearance of cysts in six subjects. After cessation of buserelin therapy, there was rapid and spontaneous ovulation which occurred within 3 weeks in all subjects. The results suggest that treatment with this GnRH agonist facilitates ovulation in this condition. Journal of Endocrinology (1990) 125, 317–325

Use of a new drug delivery formulation of the gonadotrophin-releasing hormone analogue Deslorelin for reversible long-term contraception in male dogs

2003 ◽  
Vol 15 (6) ◽  
pp. 317 ◽  
Author(s):  
A. Junaidi ◽  
P. E. Williamson ◽  
J. M. Cummins ◽  
G. B. Martin ◽  
M. A. Blackberry ◽  
...  
Keyword(s):  
Slow Release ◽  
Semen Quality ◽  
Animal Health ◽  
Plasma Concentrations ◽  
Testicular Volume ◽  
Releasing Hormone ◽  
Detectable Range ◽  
Effect Of Treatment ◽  
Gonadotrophin Releasing Hormone

In the present study, we tested the effect of treatment with a slow-release implant containing the gonadotrophin-releasing hormone agonist DeslorelinTM (Peptech Animal Health Australia, North Ryde, NSW, Australia) on pituitary and testicular function in mature male dogs. Four dogs were treated with Deslorelin (6-mg implant) and four were used as controls (blank implant). In control dogs, there were no significant changes over the 12 months of the study in plasma concentrations of luteinising hormone (LH) or testosterone, or in testicular volume, semen output or semen quality. In Deslorelin-treated dogs, plasma concentrations of LH and testosterone were undetectable after 21 and 27 days, testicular volume fell to 35% of pretreatment values after 14 weeks and no ejaculates could be obtained after 6 weeks. Concentrations returned to the detectable range for testosterone after 44 weeks and for LH after 51 weeks and both were within the normal range after 52 weeks. Semen characteristics had recovered completely by 60 weeks after implantation. At this time, the testes and prostate glands were similar histologically to those of control dogs. We conclude that a single slow-release implant containing 6 mg Deslorelin has potential as a long-term, reversible antifertility agent for male dogs.

Long-term effects of a gonadotrophin-releasing hormone agonist ([d-Ser(But)6]GnRH(1–9)nonapeptide-ethylamide) on gonadotrophin secretion from human pituitary gonadotroph cell adenomas in vitro

1988 ◽  
Vol 118 (3) ◽  
pp. 491-496 ◽  
Author(s):  
M. Daniels ◽  
P. Newland ◽  
J. Dunn ◽  
P. Kendall-Taylor ◽  
M. C. White
Keyword(s):  
Gnrh Agonist ◽  
In Vitro Release ◽  
Long Term Effects ◽  
Human Pituitary ◽  
Α Subunit ◽  
Releasing Hormone ◽  
Gonadotrophin Secretion ◽  
Gonadotrophin Releasing Hormone

ABSTRACT We have studied the effects of TRH and native gonadotrophin-releasing hormone (GnRH), and of a GnRH agonist (Buserelin; [d-Ser(But)6]GnRH(1–9) nonapeptide-ethylamide), on LH, FSH, α subunit and LH-β subunit secretion from three human gonadotrophin-secreting pituitary adenomas in dispersed cell culture. During a 24 h study, treatment with 276 nmol TRH/1 resulted in a significant (P < 0·05) stimulated release of FSH and α subunit from all three adenomas, and LH from the two adenomas secreting detectable concentrations of this glycoprotein; treatment with 85 nmol GnRH/l significantly (P < 0·05) stimulated the release of α subunit from all three, but FSH from only two and LH from only one adenoma. During a long-term 28-day study, basal FSH and α subunit concentrations were maintained, but secretion of LH, and LH-β (detectable from one tumour only), declined with time from two of the three adenomas. Addition of Buserelin to the cultures resulted in the continuous (P < 0·05) stimulation of α subunit secretion from all three adenomas, and of LH and FSH from two, whilst a transient stimulatory effect on LH and FSH secretion was seen from a third adenoma, with subsequent secretion rates declining towards control values. These data show that human gonadotrophin-secreting adenomas demonstrate variable stimulatory responses to hypothalamic TRH and GnRH, and that during chronic treatment with a GnRH agonist the anticipated desensitizing effect of the drug was not observed in two out of three adenomas studied. The mechanism for this is not clear, but such drugs are unlikely to be of therapeutic value in the management of gonadotrophin-secreting tumours. The data also suggest that GnRH and GnRH agonists have a differential effect on the in-vitro release of intact gonadotrophins and the common α subunit. J. Endocr. (1988) 118, 491–496

Gonadotrophin-releasing hormone agonist treatment for sexual offenders: A systematic review

2017 ◽  
Vol 31 (10) ◽  
pp. 1281-1293 ◽  
Author(s):  
Alexandra Lewis ◽  
Don Grubin ◽  
Callum C Ross ◽  
Mrigendra Das
Keyword(s):  
Side Effects ◽  
Outcome Measures ◽  
Sexual Offenders ◽  
Sexual Functioning ◽  
English Language ◽  
Secondary Outcome ◽  
Future Research ◽  
Releasing Hormone ◽  
Gonadotrophin Releasing Hormone

Background: Sexual offending is a significant international issue causing long-term consequences for victims, perpetrators and society. Aims: The purpose of this study was to review the existing research data assessing the efficacy of gonadotrophin-releasing hormone agonists for treating adult, male, sexual offenders. Method: The method of this review involved the examination of studies involving participants prescribed at least one month of a gonadotrophin-releasing hormone agonist for the purposes of reducing sexual drive related to offending. The primary outcome measures were recidivism rates and sexual functioning. Secondary outcome measures included assessment of side effects and effects on interpersonal/psychiatric functioning. Studies in the English language that were dated 1969–2015 were included. Results: Twelve eligible studies (323 participants) were identified. A reduction in a variety of measures of sexual functioning and/or risk was found in all studies. Robust recidivism data was limited. Medication was rarely described as ineffectual. All studies reported side effects. Reduction in bone density and potential long-term reduction in fertility in some subjects were issues of concern. Conclusion: Whilst identified studies showed promising results with respect to sexual functioning, challenges in performing randomised control trials in this subject group meant that included studies were methodologically limited. This review recommends that future research must be performed before the effectiveness and tolerability of gonadotrophin-releasing hormone agonists in this population can be confirmed.

OESTRADIOL RECEPTORS IN THE RAT ANTERIOR PITUITARY GLAND DURING THE OESTROUS CYCLE: QUANTITATION OF RECEPTOR ACTIVITY IN RELATION TO GONADOTROPHIN RELEASING HORMONE-MEDIATED LUTEINIZING HORMONE RELEASE

1978 ◽  
Vol 76 (2) ◽  
pp. 211-218 ◽  
Author(s):  
K. K. SEN ◽  
K. M. J. MENON
Keyword(s):  
Pituitary Gland ◽  
Binding Sites ◽  
Anterior Pituitary ◽  
Anterior Pituitary Gland ◽  
Oestrous Cycle ◽  
Hormone Release ◽  
Releasing Hormone ◽  
Lh Release ◽  
Gonadotrophin Releasing Hormone ◽  
Stimulation Of

Specific oestradiol binding to a receptor in nuclear and cytosol fractions of the rat anterior pituitary gland and pituitary responsiveness to gonadotrophin releasing hormone (GnRH) during the oestrous cycle have been studied. To accomplish this, both unoccupied and occupied oestradiol-binding sites in the cytosol and oestradiol-binding sites in the nucleus and total cell were measured during the oestrous cycle. The concentration of unoccupied and occupied sites and total oestradiol binding in the cytosol fluctuated during the cycle. At pro-oestrus, the concentration of cytosol receptor was diminished by about 40% and replenishment occurred during oestrus. On the other hand, a profound increase in concentrations of cellular and nuclear receptors occurred at pro-oestrus. Administration of GnRH significantly stimulated LH release at all stages of the cycle. The maximum stimulation of LH release by GnRH was observed at 13.00 h of pro-oestrus. From these studies, it is concluded that pituitary responsiveness to exogenous GnRH during pro-oestrus parallels the changes in the content of oestrogen receptors in the cytosol and nucleus.

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