Role of the ovaries in maturation of the estradiol-luteinizing hormone negative feedback system of the pubertal rat.

Abstract

ABSTRACT. The question of whether ovaries are essential for maturation of the estradiol-LH feedback system was examined. Plasma LH concentrations of rats ovariectomized (ovx) prior to puberty and infused with estradiol (E2) before puberty were compared to those of rats ovx either before or after puberty and infused after the normal age of puberty (31–38 days of age). The rats were fitted with indwelling venous catheters so that plasma LH levels could be measured by radioimmunoassay longitudinally in individual animals and E2 could be administered as a virtually continuous infusion for 1–2 weeks. The prepubertal rats were ovx at 8 or 19 days of age and infused before puberty at 25–30 days of age. Rats infused after the normal age of puberty were ovx either before puberty at 19 days of age and infused postpubertally at 41–43 or 51–58 days of age, or ovx after puberty at 60–75 days of age and then infused one week later, at 67–82 days of age. Blood samples were obtained daily between 0930–1130 h and from som...