Changes in numbers of ovarian follicles and coincident secretion of pituitary gonadotropins were characterized in suckled, anovulatory beef cows injected iv with 500 ng of luteinizing hormone-releasing hormone (LHRH) every 2 h for 48 or 96 h, starting 21.4 +_ .4 d after parturition. Two hours after the last injection, all cows were ovariectomized. Compared with saline-injected controls, LHRH ha...

The effects of the systemic administration of three prototypic multiple opiate receptor agonists, morphine sulfate (MS), ethylketocyclazocine methanesulfonate (EKC) and N-allylnormetazocine hydrochloride (NANMT), on the release of anterior pituitary hormones were studied in the rat. The serum levels of corticosterone, growth hormone, prolactin and luteinizing hormone were measured by radioimmun...

BACKGROUND Stress and corticotropin-releasing hormone inhibit the reproductive axis. We hypothesized that reproductive axis hormone secretion, particularly luteinizing hormone secretion, is inhibited in women with depression, similar to what has been observed to be caused by stress in numerous species. METHODS Blood samples were collected every 10 minutes for 12 hours in 25 untreated premenop...

Kisspeptin-Gpr54 signaling is critical for regulating the activity of gonadotropin-releasing hormone (GnRH) neurons in mammals. Previous studies have shown that the negative feedback mechanism is disrupted in global Gpr54-null mutants. The present investigation aimed to determine (1) if a lack of cyclical estrogen exposure of the GnRH neuronal network in the life-long hypogonadotropic Gpr54-nul...