[Hypophyseal gonadotropins after GnRH in patients with pituitary tumors].

The effects of exogenous GnRH on plasma FSH and LH concentrations were evaluated in 12 patients with pituitary macroadenomas and in 11 patients with pituitary microadenomas. In patients of the former group the mean values of FSH were not increased as compared with healthy controls, while LH was significantly lower. In patients of the latter group FSH was strongly greater than in normal controls, while serum LH concentrations were included in the normal range. These findings suggest that the exaggerated response of FSH can be useful to the diagnosis of the pituitary microadenomas.