[Maturation of gonadotropin function in the growing female rat. Influence of neonatal castration]

Evolution during growth of plasma level gonadotropins, was studied in the normal rat or castrated at birth. 1. In the control animals, plasma level gonadotropins decreased from the 15th to the 25th day then increased progressively to adult age. 2. Neonatal castration induced a new phenomenon: from the 25th to the 45th day, the increase of plasma gonadotropins in the normal rat corresponded with a decrease in the castrated animals; from the 45th day to the 90th day, plasma gonadotropins increased in the castrated and did not change significantly in the normal animals. 3. Ovary hormones affected gonadotropin function; however, as autonomous maturation of this function, independant of gonadal secretions, appeared to exist.