Prolactin-Secreting Pituitary Adenomas in Women. IV. Pituitary Function in Amenorrhea Associated with Normal or Abnormal Serum Prolactin and Sellar Polytomography*

Abstract

An analysis of anterior pituitary function with respect to abnormal or normal serum prolactin (hPRL) concentrations (normal, < 20 ng/ml) and sellar polytomography was performed in 84 amenorrheic women to determine whether those with hyperprolactinemia and abnormal sellar polytomograms could be distinguished from amenorrheic patients without elevated hPRL levels or abnormal tomograms. These tests fail to differentiate hyperprolactinemia resulting from a pituitary tumor from that in which no tumor can be identified. A blunted hPRL response to TRH [thyroliberin] is characteristic of hyperprolactinemia in amenorrheic patients. While cyclic endogenous gonadotropin release is impaired in hyperprolactinemic, amenorrheic women, gonadotropin responses to GnRH [gonadotropin releasing hormone] are normal or augmented. These anterior pituitary function tests do not differentiate pituitary microadenomas from macroadenomas.