Inhibitory Effects of Long Term Treatment with a Luteinizing Hormone-Releasing Hormone Agonist on the Pituitary-Gonadal Axis in Male and Female Rats

Cusan, Lionel; Auclair, C.; Bélanger, Alain; Ferland, Louise; Kelly, Paul A.; Séguin, Carl; Labrie, Fernand

doi:10.1210/endo-104-5-1369

Cited by 139 publications

(35 citation statements)

References 22 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…These effects were initially attributed to gonadotropin-induced depletion of LH receptors and desensitization of testicular steroidogenesis to subsequent hormonal stimulation (7,11,26 (28). In contrast serum testosterone levels in adult male rats treated daily with GnRH-A do not fall until 1.5-4 days after treatment (9), even though testicular gonadotropin receptors are markedly reduced within 10 hr after a single injection (13).…”

Section: Discussionmentioning

confidence: 99%

Direct inhibition of testicular function by gonadotropin-releasing hormone: mediation by specific gonadotropin-releasing hormone receptors in interstitial cells.

Clayton¹,

Katikineni²,

Chan³

et al. 1980

Proc. Natl. Acad. Sci. U.S.A.

165

View full text Add to dashboard Cite

show abstract

Section: Discussionmentioning

confidence: 99%

Direct inhibition of testicular function by gonadotropin-releasing hormone: mediation by specific gonadotropin-releasing hormone receptors in interstitial cells.

Clayton¹,

Katikineni²,

Chan³

et al. 1980

Proc. Natl. Acad. Sci. U.S.A.

165

View full text Add to dashboard Cite

show abstract

“…This has been shown to be the case for such widely diverse hormones as LH [8], luteinizing hormone-releasing hor mone [4,9], growth hormone [10], insulin [22] and thyrotrophin-releasing hormone [7], The phrase down-regula tion is frequently used to describe the negative effects of a hormone on its receptors.…”

Section: Discussionmentioning

confidence: 99%

Melatonin Given in the Morning Prevents the Suppressive Action on the Reproductive System of Melatonin Given in Late Afternoon

Chen

Brainard

Reíter³

1980

Neuroendocrinology

View full text Add to dashboard Cite

Melatonin administered to female hamsters kept under light:dark cycles of 14:10 (in hours) normally suppresses reproductive processes only if the indoleamine is administered later than 6.5 h after the beginning of the photoperiod. In the present study, we investigated the influence of morning (11.00h) injections of melatonin on the reproductive inhibitory effects of afternoon (17.00 h) melatonin injections. Adult female hamsters were exposed to light daily from 06.00 to 20.00 h. The animals were divided into the following experimental groups: group 1, injected with vehicle at both 11.00 and 17.00 h; group 2, injected with vehicle at 11.00 h and 25 μg melatonin at 17.00 h; group 3, injected with 1 mg melatonin at 11.00 h and 25 μg melatonin at 17.00 h; group 4, injected with 1 mg melatonin at 11.00 h and vehicle at 17.00 h. Control animals injected with vehicle at both 11.00 and 17.00 h had normal 4-day estrous cycles throughout the 8 weeks of the experiment. 100% of the animals injected with vehicle in the morning and melatonin in the afternoon became acyclic within 7 weeks. However, if the afternoon injections of melatonin were preceded by morning injections of the indoleamine, the animals continued to exhibit normal estrous cycles. Also, hamsters injected with melatonin at 11.00 h and vehicle at 15.00 h had normal estrous cycles throughout the study. At the conclusion of the experiment, the uterine weights and plasma prolactin levels in the animals that received vehicle at 11.00 h and melatonin at 17.00 h were depressed compared to those in the vehicle-vehicle injected controls. Again, the morning injections of melatonin prevented the afternoon injections of melatonin from decreasing either the uterine weights or the plasma prolactin levels. It is concluded that the morning injections of melatonin either down-regulated the melatonin receptors or decreased their number and thereby rendered afternoon injections of melatonin incapable of inhibiting reproductive processes.

show abstract

“…It is well known that treatment with GnRH agonists desensitizes pituitary gonadotropin secretion and down-regulates gonadal gonadotropin receptors [1,2]. On the other hand, it was reported that GnRH infusion suppressed hCG-induced ovulation in rabbits [20], suggesting direct ovarian inhibition of GnRH and its analogues in this species.…”

Section: Discussionmentioning

confidence: 99%

“…Long-term administration of gonadotropin-releasing hormone (GnRH) agonists suppresses the pituitary-gonadal functions and induces hypogonadotropic hypogonadism both in humans and experimental animals [1,2]. These agonists thus have been widely used for the treatment of sex hormone-dependent disorders such as endometriosis, uterine leiomyoma, prostatic cancer and precocious puberty [3,4].…”

Section: Introductionmentioning

confidence: 99%

Treatment with Buserelin, an Agonist of Gonadotropin-Releasing Hormone, Suppresses Ovarian Hyperstimulation Syndrome Induced in Rabbits

Oshima¹,

Suzuki²,

Makita³

et al. 2004

Pharmacology

View full text Add to dashboard Cite

Human menopausal gonadotropin (hMG, 75 IU/body/day) and a gonadotropin-releasing hormone (GnRH) agonist buserelin (1, 10, 100 µg/kg/day) were simultaneously administered to female rabbits by the subcutaneous route for 7 days, and the effects on organ weights, plasma hormones and weight of ascitic fluid were examined. Treatment with hMG increased the ovarian weight, plasma estradiol and weight of ascites, thus indicating that ovarian hyperstimulation syndrome had been induced. Simultaneous treatment with buserelin decreased the changes induced by hMG. GnRH agonists can thus be surmised to reduce the severity of ovarian hyperstimulation syndrome in the rabbit. However, caution is needed when extrapolating the results of this rabbit model to humans.

show abstract

Inhibitory Effects of Long Term Treatment with a Luteinizing Hormone-Releasing Hormone Agonist on the Pituitary-Gonadal Axis in Male and Female Rats

Cited by 139 publications

References 22 publications

Direct inhibition of testicular function by gonadotropin-releasing hormone: mediation by specific gonadotropin-releasing hormone receptors in interstitial cells.

Direct inhibition of testicular function by gonadotropin-releasing hormone: mediation by specific gonadotropin-releasing hormone receptors in interstitial cells.

Melatonin Given in the Morning Prevents the Suppressive Action on the Reproductive System of Melatonin Given in Late Afternoon

Treatment with Buserelin, an Agonist of Gonadotropin-Releasing Hormone, Suppresses Ovarian Hyperstimulation Syndrome Induced in Rabbits

Contact Info

Product

Resources

About