Bromocriptine does not inhibit the aldosterone response to sodium depletion

This study was designed to investigate the influence of the dopamine agonist, bromocriptine, on the renin-angiotensin-aldosterone system during dietary sodium restriction. Five normal white male volunteer subjects were studied in metabolic balance at constant 150 meq sodium, 60 meq potassium intake, and then daily for 7 days on an isocaloric constant diet of 10 meq sodium and 60 meq potassium/day. The subjects were studied once during administration of bromocriptine and again in the presence of bromocriptine placebo. After a stepwise daily decrease in urinary sodium excretion, sodium balance was achieved on the sixth day of low sodium intake. Renal sodium conservation in response to dietary sodium restriction was associated with parallel increases in PRA, plasma aldosterone concentration, and urinary aldosterone excretion. These changes were not significantly different during placebo and bromocriptine administration. Bromocriptine was active at the pituitary dopamine receptor, as serum PRL concentrations were suppressed to undetectable levels. The results indicate that bromocriptine does not alter the response of the renin-angiotensin-aldosterone system to sodium restriction.