The effect of low dose carbidopa/levodopa on prolactin and growth hormone concentrations in patients with breast cancer and in benign breast tumours.

1 Low doses of carbidopa/levodopa (12.5 mg 1-alpha-methyl-dopahydrazine, 125 mg levodopa) were administered orally to 29 patients with tumours of the breast (16 with breast cancer, 13 with benign breast disease). 2 Plasma dopa response curves were similar in all the patients studied. 3 Prolactin and growth hormone showed similar responses to carbidopa/levodopa irrespective of age or diagnosis. 4 Prolactin showed an unusual reponse in four patients which has not previously been recorded.