Long-term trophic effect of sodium restriction on the rat adrenal zona glomerulosa. II. The possible involvement of the inhibition of the dopaminergic system.

The effects of chronic administration of metoclopramide or bromocriptine (two drugs which act as antagonist and agonist of dopamine receptors) on the zona glomerulosa of captopril-treated rats administered maintenance doses of angiotensin II, were investigated by combined morphometric and biochemical techniques. It was found that metoclopramide provoked a significant hypertrophy of the zona glomerulosa and its parenchymal cells, coupled with a persistent rise in the plasma concentration of aldosterone, only in rats fed a normal diet. Conversely, bromocriptine exerted an evident inhibitory effect on the zona glomerulosa growth and steroidogenic capacity only in chronically sodium-deprived animals. These findings strongly suggest that sodium balance modulates the activity of the dopaminergic system, whose chronic suppression may be involved in the mechanism underlying the extra-angiotensin adrenoglomerulotrophic effect of prolonged sodium restriction.