Serum estradiol and prolactin concentrations in neonatal female rats treated with human chorionic gonadotropin (hCG).

Abstract

The induction of a syndrome characterized by lack of ovulation or corpora lutea formation, and with constant vaginal estrus, following treatment of neonatal (beginning on day 6) female rats with human chorionic gonadotropin (hCG) was confirmed. Ten daily subcutaneous injections of 10 IU (days 6–15) produced this syndrome in all of the females by 60 days of age. Serum estradiol concentrations and uterine weights were increased on day 11 after 5 injections of hCG, but neither ovarian weights nor serum prolactin levels were different from control values. After 10 injections of hCG (day 16) ovarian and uterine weights were three times control values. Serum estradiol concentrations reached peak values of 434 pg⁄ml in these animals and prolactin levels were twice those of controls. Between day 16 and day 21 ovarian weights increased nearly 3-fold in both control and hCGtreated females, but only the latter animals had increased uterine weights. Serum estradiol was lower on day 21 than on day 16, but prolactin ha...