Serum aldosterone response to metoclopramide in normal subjects and acromegalic patients

The acute effects of metoclopramide on aldosterone and prolactin levels were studied in 11 normal subjects, 8 normotensive and 8 hypertensive acromegalics. Metoclopramide (10 mg i.v.) induced a similar serum aldosterone increase in normal subjects and normotensive acromegalics. Hypertensive acromegalics showed elevated basal serum aldosterone level and blunted aldosterone response to metoclopramide. The prolactin response to metoclopramide was blunted in acromegalics in comparison with normal subjects but the difference was statistically significant only in hypertensive patients. The blunted aldosterone and prolactin responses to metoclopramide in hypertensive acromegalics suggest that there is a dopamine deficiency at central and adrenal level in these patients.