Dopaminergic modulation of corticosteroid responses to angiotensin II in man

This study was designed to investigate dopaminergic mechanisms involved in the control of corticosteroid secretion in man. Plasma cortisol, corticosterone, 11-deoxycorticosterone, 18-hydroxycorticosterone (18-OHB), and aldosterone responses to graded doses of angiotensin II and ACTH were evaluated in six healthy male volunteers with and without treatment with the dopamine agonist bromocriptine (BEC). Angiotensin II infusion resulted in parallel responses of 18-OHB and aldosterone without affecting other precursors of the aldosterone biosynthetic pathway. BEC (2.5 mg tid for 6 days) markedly suppressed basal supine plasma 18-OHB levels without affecting basal levels of aldosterone. Basal supine plasma corticosterone levels were increased after BEC treatment. BEC treatment inhibited the 18-OHB and aldosterone responses to graded infusions of angiotensin II. Plasma 18-OHB responses to ACTH infusion were not altered by BEC treatment. Other factors renin activity and serum electrolytes were not altered by BEC administration. These results suggest that angiotensin-mediated 18-OHB and aldosterone secretion is selectively inhibited by dopaminergic mechanisms.