The importance of sodium balance on the effect of angiotensin II on aldosterone production.

The action of angiotensin II on the adrenal cortex can be modified by body sodium balance. The secretion rate of aldosterone was compared with the late biosynthetic pathway in dogs kept under different sodium states. The conversion of corticosterone (B) to aldosterone was significantly increased by the infusion of angiotensin II into sodium depleted dogs. ACTH infusion failed to increase the late aldosterone pathway in sodium depleted animals, even though the secretion rate increased by 10 times. These results confirm previously indirect evidence that angiotensin II has a direct stimulatory effect on the late step of aldosterone biosynthesis. This stimulation does not appear to be the result of enzyme-substrate activation by aldosterone precursors. The results favour the hypothesis that sodium balance can modulate the action of angiotensin II not only on the first steps, but that there is also a regulatory effect on the conversion of corticosterone to aldosterone.