Dose related effect of a single injection of progesterone on gonadotropin secretion and pituitary sensitivity to LHRH in estrogen-primed castrate female rats.

摘要: This investigation studied the effect on gonadotropin secretion of varying doses progesterone given as a single injection to estrogen-primed castrated rats. Female rats were ovariectomized at 26 days age (Day 1) and administered 0.1 Mg/kgBw estradiol-17fl for 4 starting day castration. Progesterone, in various doses, was 0930 h fourth postcastration groups animals sacrificed between 1000 1600 h. Estrogen treatment reduced but did not suppress rise gonadotropins. In 0.2 or 0.8 mg/kgBW progesterone, there significant increase both serum follicle stimulating hormone (FSI-I) luteinizing (LH) by estrogenprimed 0.4 3.2 suppression FSH LI-I By 1800 LH had returned baseline levels all groups. Estrogen-primed then 10 ng pulses releasing (LHRH) 2000 2200 bled 0, bO, 60 120 after each pulse. There dose related pituitary’s response LHRH. The mg stimulatory inhibitory compared with estrogen treated controls LFI. For FSH, no difference increment LHRH nonprogesterone Between 2 groups, however, significantly higher than dose. Pituitary content increased addition demonstration direct pituitary effect, this study shows that is dependent under conditions uniform stimulation time exposure progesterone.