In vitro uptake of tritiated sex steroids by the hypothalamus of adult male rats treated neonatally with an antiandrogen (cyproterone).

Abstract

ABSTRACT Male rats were injected subcutaneously with 2 mg of cyproterone daily from birth to the 14th postnatal day. At the age of 40 days the animals were polycystic and corpora lutea were absent. There was an increased 37% of the ovarian implants showed distinct corpora lutea indicating cyclic secretion of gonadotrophins; the implants in the control animals were polycystic and corpora lutea were absent. There was an increased interstitial cell stimulating hormone output from the pituitary gland as indicated by the increased amount of 3β-hydroxysteroid dehydrogenase active Leydig cells in the testes of the feminized animals. The in vitro uptake of tritiated testosterone and oestradiol of various tissues was tested on rats, age 4.5 months. The anterior hypothalamus, the rostral middle hypothalamus, the median eminence and the anterior pituitary of the feminized males retained significantly more oestradiol than the cerebral cortex. The oestradiol uptake in these areas also exceeded that of the control animals. Only the median eminence of the cyproterone treated rats concentrated more testosterone than the cerebral cortex. The anterior hypothalamus and cerebral cortex of the feminized male rats were less able to transform tritiated testosterone to dihydrotestosterone or tritiated oestradiol to oestrone, as compared to adult castrated male or female animals, respectively.