DIFFERENTIAL RESPONSE TO LHRH FOLLOWING OESTROGEN THERAPY IN WOMEN WITH AMENORRHOEA

Summary

The effect of administering 2.5 mg oestradiol benzoate upon subsequent response to 100 ug synthetic luteinizing hormone releasing hormone (LHRH) was investigated in 24 women with amenorrhoea but with no demonstrable pituitary or ovarian cause and in whom serum prolactin levels were within the normal range. Differential responsiveness to LHRH was observed when re-testing the subjects 44 hours following the oestrogen administration. Twelve out of 24 subjects showed an augmentated LH response, the post-treatment response similar to that observed in normal regularly menstruating females when tested in the follicular phase of their cycles. In 11 of these 12 patients ovulation could be induced by clomiphene. The remaining 12 patiens failed to show an augmentation of LH response and indeed had a suppressed post-treatment response. In this group of subjects a significantly lower basal serum oestradiol-17β level was found (p <0·01) and none of these patients ovulated following clomiphene administration. This differential responsiveness to LHRH following oestrogen therapy in patients with amenorrhoea of‘hypothalamic’ origin further subdivides this heterogeneous group into two sub-groups who respond to clomiphene administration in a different manner and sheds further light upon the pathogenic mechanism of gonadotrophin release in such patients.