Characterization of rat capsular adrenal (zona glomerulosa) (Na,K)-ATPase activity.

A higher (Na,K)-ATPase activity was found in rat capsular (zona glomerulosa) than in decapsulated (zona fasciculata) adrenal. No unusual characteristics of this enzyme were found in the simulation with Na+ and K+ and the inhibition with ouabain. Angiotensin II, ACTH and serotonin, all potent stimulators of aldosterone biosynthesis, did not affect the enzyme. In conclusion, the characteristics of rat capsular adrenal (Na,K)-ATPase are identical to the classical enzyme. It is not the direct receptor or effector for stimulators of aldosterone biosynthesis but a supportive role in mediating the regulatory signal cannot be ruled out.