MODULATION OF PITUITARY RESPONSES TO SYNTHETIC LH-RH BY GONADAL STEROIDS IN WOMEN WITH SECONDARY AMENORRHOEA

Abstract

LH-RH [luteinizing hormone-releasing hormone] stimulation tests were performed on 2 successive days in 25 women with secondary amenorrhoea of probable hypothalamic origin by i.v. injection of 150 .mu.g of synthetic LH-RH. The patients were selected by exclusion of definite pituitary or ovarian disease and in the absence of clinical or laboratory evidence of androgen excess. Five women received successive LH-RH stimulation tests only without administration of steroid hormone. Twenty women were treated with gondal steroids in addition to the double LH-RH stimulation test by i.m. injection of the steroid 4 h after the 1st LH-RH injection. On these 20, 9 received estradiol (E2), 5 received progesterone (P) and 6 received E2 + P. Gonadotropin responses to LH-RH in successive tests without steroid were not significantly different. E2 or P alone each produced suppression of LH and FSH [follicle stimulating hormone] responses to LH-RH in the 2nd test as compared to the 1st. Combined E2 + P produced augmentation or suppression of the 2nd gonadotropin responses depending on the dose of E2 administered. The results demonstrate a direct effect of estrogen or P alone and in combination on the pituitary responsiveness to LH-RH. The effect of the combined steroids can be modified by variations in the estrogen:P ratio.