The effect of synthetic corticosteroids on ovarian function in the baboon

Parenteral injection of triamcinolone at the time of menstruation or during the early stage of follicle development blocked ovulation and advanced the time of the following menstruation in baboons. The steroid was less effective if given during the immediate preovulatory phase. Injection of triamcinolone at the time of menses for 2-7 consecutive cycles consistently disrupted follicle development and ovulation. The menstrual cycles were shortened, but the actual cycle lengths were quite consistent and regular. Administration of 50 mg cortisol at the time of menstruation did not affect the following menstrual cycle and ovulation. It is inferred that a synthetic corticosteroid can exert important effects on the gonadotrophin regulatory mechanism in the baboon and that the contrast or similarity of the natural corticosteroid to synthetic corticosteroid bears further investigation.