LH and FSH responses to GnRH in health and disease

LH and FSH responses to intravenous bolus GnRH were evaluated in healthy men and women and in patients with various hypothalmo-pituitary disorders. Higher LH FSH responses to GnRH were recorded. In prepubertal girls FSH responses were higher than those of LH; however, while FSH responses remained unaltered through pubertal development stages 2-5, there was a progressive increase in LH response during that period. GnRH test was marginally useful in diagnosis of delayed puberty but more so in hypogonadotropic hypogonadism and true precocious puberty. In experimental hyperprolactinemia, GnRH induced a near normal LH response but caused an exaggerated FSH response, which was normalized after clomiphene treatment. GnRH test was found to be useful to assess pituitary reserve of gonadotropins in a variety of clinical situations involving hypothalamo-pituitary gonadal axis.