Isopycnic density values for lysosomes and mitochondria in rat adrenal cortex

Adrenocortical tissues of male adult Wistar rats were fractionated by isopycnic density gradient centrifugation. Fractions were analyzed for density, protein and marker enzymes for lysosomes and mitochondria with rat liver being used as a reference tissue for subcellular enzyme distribution. Both lysosomes and mitochondria of adrenal cortex showed unimodal distribution profiles of marker enzymes with their modal isopycnic density values at 1.165. This value was significantly lower than the corresponding ones for lysosomes and mitochondria in rat liver but was very close to those in porcine adrenal cortex. Modal isopycnic density as well as distribution profiles of marker enzymes for lysosomes and mitochondria remained unchanged 24 hr after 0.1 or 10 units of ACTH (Cortrosyn Z) administration. As in porcine adrenal cortex, lysosomes in rat adrenal cortex were characterized by a higher content of cathepsin D than those in rat liver.