Human pituitary gonadotrophin index. II LHRH test and clomiphene response before and after LHRH stimulation

To monitor the effect of LHRH treatment on hypothalamo-pituitary-gonadal function, women with functional amenorrhoea were investigated by standardized LHRH and repeated clomiphene tests before and after LHRH therapy. The actual pituitary gonadotrophin reserve was defined by a Human Pituitary Gonadotrophin Index (HPGI). Clomiphene response served as hypothalamic function test, plasma oestradiol and progesterone concentrations were measured for assessment of the gonadal function. LHRH treatment as performed in this study did not change basal gonadotrophin levels or the pituitary responsiveness in our standardized LHRH test. Plasma oestradiol concentrations remained unaltered at the lower limit of the early follicular phase values of a normal menstrual cycle. The inability to respond to clomiphene was changed to clomiphene responsiveness during therapy in eighteen out of twenty-nine women with anovulation. The majority of the responders had HPG-Indices of R2. Patients with hyperprolactinaemic anovulation did not convert. The possibility of an ultrashort feedback action of LHRH on its own production in the human is discussed.