Adrenal renin: a possible local hormonal regulator of aldosterone production.

The complete renin-angiotensin system is present in the adrenal cortex: prorenin, renin, angiotensinogen, angiotensin I and II, and converting enzyme. Most of the renin found is probably synthesized there since the renin concentration increases after nephrectomy, and the mRNA for renin is present. The renin-angiotensin system has the highest activity in the zona glomerulosa cells, the site of aldosterone formation. A low-sodium diet or a high-potassium diet, or nephrectomy markedly increases the adrenal renin concentration in the zona glomerulosa cells without any effect on the fasciculata-medullary cells. There is a close correlation between adrenal renin and aldosterone production. The adrenal renin angiotensin system may be a local regulator of aldosterone production.