Levels of cytochrome P-450, steroidogenesis and microsomal and cytosolic epoxide hydrolases in normal human adrenal tissue and corresponding tumors.

The levels of microsomal cytochrome P-450, steroidogenesis and microsomal and cytosolic epoxide hydrolase activities in normal human adrenal tissue (obtained from adult kidney transplant donors and autopsy material) and corresponding hyperplasia, adenomas and carcinomas (surgical biopsies) were determined. The increased steroid production demonstrated by most of the pathological tissue samples examined here was associated with either an unchanged or dramatically decreased specific microsomal content of cytochrome P-450. Furthermore, specific microsomal epoxide hydrolase activity was also found to be reduced in adrenocortical carcinomas, while the corresponding cytosolic activity was also decreased in at least two of these carcinomas. It is of interest to note in this connection that the level of microsomal epoxide hydrolase in slightly atropic adrenal cortex surrounding adrenocortical carcinomas was also found to be reduced. This would indicate that despite its appearance, this surrounding tissue is not normal in all respects. Thus, adrenocortical carcinomas fit into the common pattern in that their specific contents of microsomal cytochrome P-450 are dramatically decreased, but the simultaneous decrease in their microsomal epoxide hydrolase activity is more unusual.