Ectopic Production of Prolactin

Abstract

Markedly elevated serum prolactin levels were observed in a patient with undifferentiated bronchogenic carcinoma and in a patient with galactorrhea and hypernephroma. Irradiation of the bronchogenic carcinoma was associated with a decrease in the serum prolactin concentration from 100 to 20 ng per milliliter, and surgical resection of the hypernephroma reduced the serum prolactin concentration from 150 to less than 2 ng per milliliter. Production of prolactin was directly demonstrated in tissue cultures of the hypernephroma. The prolactin activity was found to be identical to authentic prolactin by its biologic activity on organ cultures of mammary gland and by the specificity of its immunologic reactivity with antiprolactin antibodies. These studies demonstrate the ectopic production of prolactin by human cancer cells, and the results suggest that carcinoma should be considered in the differential diagnosis of patients with galactorrhea or hyperprolactinemia.