Hyperprolactinemia in sarcoidosis: incidence and utility in predicting hypothalamic involvement.

Patients with sarcoidosis have been reported frequently to have elevated concentrations of serum prolactin. On this basis, it was suggested that the hypothalamus might be a common site of involvement by sarcoidosis and that measurement of serum prolactin concentrations might serve as a sensitive indicator of hypothalamic disease. We measured serum prolactin concentrations in a group of 61 patients with sarcoidosis. Hyperprolactinemia was detected in only 2 of the entire group and was not observed in any of the 9 patients with central nervous system involvement. Because radioimmunoassayable prolactin concentrations are infrequently elevated in patients with disseminated sarcoidosis, even when pitutitary hypofunction is apparent, it is concluded that the measurement of serum prolactin is not a reliable method for screening these patients for pituitary or hypothalamic disease.