Assessment of pituitary secretory capacity in women with hypogonadotrophic hypogonadism by using a long-acting synthetic analogue of luteinizing hormone releasing factor.

Abstract

The gonadotrophin responses to single and repeated injections of a long-acting synthetic analogue of luteinizing hormone releasing factor (LRF), d-Ser(TBU)6EA10LHRH, were investigated in 10 women with normoprolactinaemic hypogonadotrophic hypogonadism. Abnormal luteinizing hormone (LH) responses were observed in two of the five patients treated with 5 micrograms of the analogue and in all five patients treated with three injections of 10, 20 and 10 micrograms administered at intervals of 10-14 h. However, the LH response to repeated injections of the analogue was of similar magnitude and duration to that observed in normal women in response to an oestrogen provocation test in the early-to-mid follicular phase of the cycle. Thus failure of the LH response to oestrogen provocation in women with hypogonadotrophism results from hypothalamic rather than primary pituitary dysfunction. This study confirms the usefulness of this analogue of LRF in the assessment of pituitary secretory function in women with abnormal responses to oestrogen positive feed-back.