Serum prolactin in liver disease and its relationship to gynaecomastia.

Serum immunoreactive prolactin was measured in 150 patients with liver disease of varying aetiology and severity and in 45 control subjects. The upper limit of the reference range for serum prolactin was 331 mU/l. Eighteen patients with liver disease (12%) had unexplained hyperprolactinaemia. No relationship existed between the prolactin value and the sex of the patient, the aetiology of the liver disease, the severity of the liver disease, or the presence of gynaecomastia. The cause of the hyperprolactinaemia in patients with liver disease and its clinical implications need further investigation.