Serum prolactin levels in eighty patients with sarcoidosis.

Serum prolactin levels were measured by radioimmunoassay in eighty patients (thirty-four males, forty-six females) with sarcoidosis before treatment. In twelve patients (15%) serum prolactin levels were more than two standard deviations above the mean of normal subjects. Hyperprolactinaemia was found most frequently (22%) in patients with radiological stage II; however, 14% of patients with stage I also had elevated serum prolactin levels. In most cases serum prolactin levels fell to within the normal range after treatment with corticosteroid in parallel with improvement of intrathoracic lesions. These findings suggest that hyperprolactinaemia may be due to hypothalamic involvement by sarcoid granulomata. We conclude that the measurement of basal serum prolactin levels using radioimmunoassay is a sensitive and practical method for screening patients with sarcoidosis for hypothalmic lesions.