THE EFFECT OF INITIAL AGE ON THE RESPONSE OF THE RAT TO TREATMENT WITH GONADOTROPHINS

Abstract

ABSTRACT In the rat, the age at which the maximum response to gonadotrophin treatment will occur is dependent on both the parameter being examined and the hormone, or combination of hormones used. Thus, the ovulation rate following treatment with pregnant mares' serum gonadotrophin (PMSG) alone, or in combination with human chorionic gonadotrophin (HCG), is maximal at an earlier age than that observed for HCG alone. From the data presented, it would seem that, for the conditions employed, the optimal age of animals for studies on gonadotrophin-induced ovulation would be approximately thirty days.