Further Studies on the Involvement of Dopamine and Somatostatin in the Inhibitory Control of the Growth and Steroidogenic Capacity of Rat Adrenal Zona Glomerulosa

Summary

Prolonged (12-day) sodium restriction increased basal plasma concentration of aldosterone and provoked a notable hypertrophy of the zona glomerulosa and its cells in rats. A 7-day infusion of dopamine or somatostatin, at a rate which was found to exert a maximum inhibition of aldosterone secretion in 12 h, only partially reversed the effects of sodium deprivation. However, the combined administration of these two molecules not only completely annulled the effects of sodium restriction, but also lowered plasma aldosterone concentration and the volumes of the zona glomerulosa and its cells below the values found in rats fed a normal diet. These findings confirm the contention that dopamine and somatostatin are both involved in the negative control of the growth and steroidogenic capacity of the rat zona glomerulosa, and suggest that different mechanisms underlie the antiadrenoglomerulotrophic action of these molecules.

Key Words

Zona glomerulosa - Dopamine - Somatostatin - Sodium restriction - Aldosterone - Rat