Steroidogenesis in isolated adrenal cells of rat. 3. Morphological and biochemical correlation of cholesterol and cholesterol ester content in ACTH and N6-2'-O-dibutyryl-adenosine-3',5'-monophosphate activated adrenal cells.

Electron microscopic studies of isolated rat adrenal cells, prepared by trypsin digestion, showed that this preparation consisted of more than 90% of fasciculata cells and less than 10% reticularis, glomerulosa and medullary cells. Morphological studies of isolated adrenal cells after incubation with and without ACTH or dibutyryl cAMP (dcAMP) showed that: a) the cell membrane remained intact with minimal amount of mitochondrial swelling; b) ACTH or dcAMP caused few morphological changes discernible by the electron microscope; and c) no significant depletion of the lipid globules occurred in response to ACTH or dcAMP in spite of active time dependent corticosterone synthesis. Chemical analysis of endogenous cholesterol and cholesterol ester, as well as analysis of pulse labeled endogenous total cholesterol, revealed no significant decrease of cholesterol in response to ACTH or dcAMP. Studies on cholesterol synthesis from labeled mevalonic acid suggested that an additional action of ACTH may be the regulati...