Enzyme histo-cytochemical studies in human adrenocortical adenomas. [II] Cushing's syndrome.

Enzyme histo-cytochemical staining was performed for 3 beta-hydroxysteroid dehydrogenase, alkaline phosphatase and acid phosphatase in the compact and clear cells of the adrenocortical adenomas associated with Cushing's syndrome (Cushing's adenomas). In the compact cells, enzymatic activities of 3 beta-hydroxysteroid dehydrogenase and alkaline phosphatase were stronger than those in the clear cells. Electron microscopic localization of alkaline phosphatase was mostly present on well developed microvilli, while, acid phosphatase was observed in lysosomes near the well developed smooth endoplasmic reticula. On the other hand, in the clear cells, cytochemical localization of alkaline phosphatase was mainly present on the intercellular plasma membrane, while acid phosphatase was mostly observed near the lipid droplets. Based on these data, functional aspects of the compact and clear cells in Cushing's adenomas are discussed.