Regulation of oestrogen-induced LH release in male and female marmoset monkeys (Callithrix jacchus).
The positive-feedback action of oestradiol-17 beta on LH release was studied in gonadectomized male and female and intact male marmoset monkeys. Positive feedback was observed in normal intact males in response to a single subcutaneous injection of 35 micrograms oestradiol benzoate. The sustained elevation in oestradiol-17 beta levels achieved by the injections resulted in a marked suppression of circulating testosterone concentrations. Subcutaneous injections (0.5 mg/injection) of testosterone or dihydrotestosterone to gonadectomized males and females immediately following and 8 h after oestradiol benzoate failed to inhibit positive feedback. Similar treatment with progesterone (1.0 mg/injection) tended to standardize both positive and negative components of the feedback response. In contrast, progesterone implants (achieving progesterone concentrations similar to those obtained with the injections), maintained during and for 8 days before the oestradiol benzoate treatment, effectively inhibited positive feedback. LH responses to the various treatments were similar in gonadectomized males and females. These data suggest a relative unimportance of testicular secretions in suppressing oestrogen-induced LH release in the adult marmoset and indicate similarities between the control of positive feedback in male and female primates.
D000818:Animals; D002143:Callitrichinae / Q000502:physiology*; D002369:Castration; D013196:Dihydrotestosterone / Q000494:pharmacology; D004958:Estradiol / Q000494:pharmacology*; D005246:Feedback; D005260:Female; D007986:Luteinizing Hormone / Q000378:metabolism*; D008297:Male; D011374:Progesterone / Q000494:pharmacology; D012636:Secretory Rate / Q000187:drug effects; D013739:Testosterone / Q000494:pharmacology
D013196:Dihydrotestosterone; D013739:Testosterone; D011374:Progesterone; D004958:Estradiol; D007986:Luteinizing Hormone