The authors studied the blood aldosterone, cortisol, and kalium levels, the plasma renin activity and the aldosterone urinary excretion following L-Dopa (0,50 g per os) administration in five patients affected by hypertension and six healthy control subjects, before and after the CRF-ACTH system suppression. The observed pattern shows that the aldosterone biosynthesis is inhibited also after the CRF-ACTH system has been suppressed. Therefore the authors conclude that the inhibiting action of L-Dopa on the aldosterone biosynthesis is mediated by the dopaminergic system stimulation.