EFFECTS OF ANTIPROGESTERONE RU486 ON GONADOTROPIN-SECRETION IN INFANTILE AND JUVENILE FEMALE RATS - EVIDENCE FOR AN EXTRAOVARIAN EFFECT

The three day administration of antiprogesterone RU486 to infantile (8 days old) and Juvenile (25 days old) intact female rats results in a reduction in the peripheral concentration of LH without affecting that of FSH. Bilateral ovariectomy induced significant increases in the concentrations of FSH at both ages, but only increased the LH concentration in juvenile rats. Antiprogesterone treatment reduced post-ovariectomy increases in both LH and FSH. Results indicate an extraovarian effect of antiprogesterone RU486 and suggest a direct effect at the hypothalamus-pituitary axis.