Stereological and biochemical investigations on a possible aldosterone-containing secretory organelle in the zona glomerulosa of rat adrenal gland.

Chronic angiotensin treatment induced a significant increase in the number of dense bodies in rat zona glomerulosa cells. The possible lysosomal nature of these organelles can be excluded, since in the zona glomerulosa of the treated animals the intracellular activity of some lysosome-marker enzymes (acid-phosphatase, beta-glucuronidase, and N-acetyl-beta-glucosaminidase) did not display significant changes. Stereological and radioimmunological analysis demonstrated that the angiotensin-induced increase in the volume density of dense bodies was associated with a comparable increase in the intracellular concentration of aldosterone. The hypothesis of the secretory nature of these granules is discussed.