EFFECTS OF A NEW ORAL PROGESTAGEN ON PITUITARY-OVARIAN FUNCTION

Abstract A new progestagen, Org 3236 (13-ethyl-11-methylene-18, 19-dinor-17α--pregn-4-en-20-yn-3-one), which is a 3-keto derivative of another new progestagen, Org 2969 (13-ethyl-11-methylene-18,19-dinor-17α-pregn-4--en-20-yn) was administered to seven healthy female volunteers in doses 0.025 mg/day (3 volunteers) and 0.050 mg/day (4 volunteers) to evaluate its biological properties. The function of the hypophyseal-ovarian axis was tested by measuring serum follicle stimulating hormone, luteinizing hormone, estradiol and progesterone daily on days 7–23 of two consecutive cycles, of which the first served as a control. Org 3236 was given on days 1–21 during the second menstrual cycle. The results revealed that ovulation was inhibited in 3 out of 4 volunteers with the 0.050 mg daily dose. Also in the fourth volunteer the occurrence of ovulation is questionable. In the group with a daily dose of 0.025 mg two of the three volunteers had anovulatory treatment cycles. The ovulation inhibiting activity of Org 3236 is comparable to that reported for Org 2969.