Prolactin response to thyrotropin-releasing hormone stimulation and dopaminergic inhibition in benign breast disease.

Pituitary function was tested in predefined clinical groups of benign breast disease under strictly controlled clinical and laboratory conditions. Two different tests of prolactin storage and control mechanisms, direct stimulation by thyrotropin-releasing hormone (TRH) and inhibition of dopaminergic control by domperidone, indicate a significant abnormality in patients with severe cyclical mastalgia and nodular breast disease (P less than 0.05 and P less than 0.002), but not in those with noncyclical mastalgia. No abnormalities of thyroid function were found.