Inhibition of Prolactin Secretion and Successful Therapy of the Forbes-Albright Syndrome with<scp>l</scp>-Dopa*

Abstract

Fourteen patients with galactorrhea, elevated serum prolactin levels (10–1130 ng/ml), and decreased urinary excretion of gonadotropins (Forbes-Albright syndrome) were treated with oral l-dopa for 6 months. l-dopa effected a rapid decrease in the serum prolactin level to normal or nearly normal in 11 patients who experienced complete cessation of galactorrhea. Withdrawal of l-dopa was associated with the return of pro-lactin levels to the initial control values and with resumption of galactorrhea. l-Dopa also increased urinary gonadotropin excretion in the successfully treated patients with resumption of menses in 4 pre-menopausal subjects. Two of the patients who failed to respond well to this therapy were subsequently found to have pituitary chromophobe adenomas. These results indicate that l-dopa may be useful in the chronic medical management of patients with “idiopathic” galactorrhea and associated amenorrhea.