[Maturation of gonadotropin function during growth of the male rat: influence of neonatal castration (author's transl)].

Evolution during growth of plasma level gonadotropins, was studied in the normal or castrated rat at birth. In the control animals, the plasma level of gonadotropins increased from the 25th day to the 40th day, then declined to the 90th day. Neonatal castration induced a new phenomenon: the increase of plasma gonadotropins in the normal rat corresponded with a decrease in the castrated animals and inversely. Testis hormones affected gonadotropin function; however, an autonomous maturation of this function, independent of gonadal secretions, appeared to exist.