In this paper a mathematical model is developed based on current biological concepts of the lamprey GnRH-III involved in LH and FSH concentration . The physiologic role played by GnRH-III on gonadotropin secretion in mammalian species is controversial. Although GnRH-III is a weak GnRH agonist, early research in mammalian species suggested that GnRH-III can selectively stimulate the secretion of...

We investigated the importance of inhibin and testosterone in the regulation of gonadotropin secretion in adult male golden hamsters (Mesocricetus auratus). After castration, plasma concentrations of inhibin and testosterone were reduced to undetectable, whereas plasma follicle-stimulating hormone (FSH) and luteinizing hormone (LH) were increased. After hemicastration, plasma FSH and LH increas...

The ovarian response to stimulation with folliclestimulating hormone/luteinizing hormone-releasing hormone (FSH/LH-RHI) was studied in young, healthy, and fertile women with constant iatrogenic anovulation caused by depot medroxyprogesterone acetate or depot chlormadinone acetate injected for contraceptive purposes. Results were compared with those in unstimulated controls. The response was obs...

The effects of the gonadotrophin-releasing hormone, synthetic decapeptide luteinizing hormone/follicle stimulating hormone-releasing hormone (LH/FSH-RH), have been studied in 18 normal men and five women in the follicular phase of their menstrual cycle. Rapid and dose-dependent (25 to 100 mug) increases in serum immunoreactive LH were seen, which reached a peak 20 to 30 minutes after a rapid in...

Hypothalamic tissues of female rats were extracted with 1.M acetic acid. The acidic extract was lyophilized and subjected to gel filtration on Sephadex column and assayed for follicle-stimulating hormone-releasing factor (FSH-RF) activity and luteinizing hormone-releasing factor (LH-RF) activity by estimating FSH and LH using the organ culture method of rat anterior pituitaries. FSH activity wa...

The effect of naloxone on GnRH-induced LH and FSH release was measured in buffaloes in luteal phase of estrous cycle. Animals were administered intravenously, naloxone/saline (50 mg/injection) every 15 min for 3 hr followed by GnRH (100 micrograms). Peripheral plasma LH and FSH concentrations were measured in blood samples collected at 15 min intervals from 1 hr prior to beginning of naloxone/s...

Serum anti-Müllerian hormone (AMH) levels are regarded as an age-specific marker for predicting the ovarian reserve in women of reproductive age. Some studies have shown that the luteinizing hormone (LH)/follicle stimulating hormone (FSH) ratio can be used as a predictor of ovarian reserve. The purpose of this study was to assess the variation of LH/FSH ratio with aging and to evaluate the corr...

Horse LH/chorionic gonadotrophin (eLH/CG) exhibits, in addition to its normal LH activity, a high FSH activity in all other species tested. Donkey LH/CG (dkLH/CG) also exhibits FSH activity in other species, but about ten times less than the horse hormone. In order to understand the molecular basis of these dual gonadotrophic activities of eLH/CG and dkLH/CG better, we expressed, in COS-7 cells...