Effects of a new oral progestagen on pituitary-ovarian function

Effects of two oral contraceptive combinations, 0.125 mg desogestrel + 0.050 mg ethinylestradiol and 0.125 mg levonorgestrel + 0.050 mg ethinylestradiol on the adrenal function of healthy female volunteers

The effects of the oral contraceptive combinations of 0.125 mg desogestrel + 0.050 mg ethinylestradiol (EE), and of 0.125 mg levonorgestrel + 0.050 mg EE on serum cortisol and the urinary excretion of 17-oxogenic steroids and free cortisol were studied in 16 healthy females. Adrenal responsiveness was studied by the metyrapone test. Both contraceptive combinations increased (P less than 0.001) serum cortisol concentrations but the rhythmic fluctuation at different times of the day remained unchanged. The urinary excretion of 17-oxogenic steroids was lower (P less than 0.01) during treatment than before or after treatment with both contraceptive combinations. The metyrapone test showed normal adrenal responsiveness during the treatment cycles. The urinary excretion of free cortisol was unchanged when desogestrel + EE was used, but increased (P less than 0.01) during treatment with levonorgestrel + EE. However, even then, the urinary free cortisol was within the normal range of the population. All the test results of hormone determinations normalized soon after finishing the contraceptive treatments. It is suggested that the abnormalities seen were due to an increased serum binding capacity of cortisol induced by EE and not a sign of pathological changes in adrenal function. No major differences in the biological effects of the two combinations tested were seen.

Pituitary and ovarian function during contraception with one subcutaneous implant releasing a progestin, ST-1435

Three women received one subcutaneous SilasticR capsule containing 40 mg of ST-1435 for contraception. Plasma levels of ST-1435, a 19-norprogesterone derivative, were measured during the treatment period of 13-15 months. The effects of treatment on pituitary and ovarian function were determined by assaying plasma concentrations of LH, FSH, estradiol and progesterone. The mean concentrations of ST-1435 during the treatment varied from 52 to 220 pg/ml in different subjects. These low concentrations of progestin were sufficient to suppress ovulation and make the implant effective for more than one year. No mid-cycle gonadotropin peaks were observed during the treatment. The subjects showed constantly low estradiol levels, thus also indicating a suppression of follicle development. Regular cyclic activity of the pituitary and ovaries, without the occurrence of ovulation, was observed in one subject. Increasing levels of estradiol parallelled a decrease of FSH and LH. It therefore seems that the negative feedback action of estradiol on gonadotropin release is unaffected but the positive feedback action of estradiol on LH appears to be blocked by the progestin ST-1435.