Transmembrane potentials and steroidogenesis in normal and neoplastic human adrenocortical tissue

Trans-membrane potentials and steroidogenesis were measured in superfused slices of non-tumor and neoplastic human adrenocortical tissue. Non-tumor tissue was obtained at the time for renal transplant or from tissue removed along with tumors. Non-tumor human adrenocortical tissue had electrophysiological and steroidogenic properties similar to those of the rat and rabbit. In normal medium ACTH stimulated steroidogenesis but had no effect on the membrane potential. In K+-free medium, the cells hyperpolarized, and subsequent addition of ACTH caused depolarization. Trans-membrane potentials of adrenocortical tumors were lower than those of non-tumor cells. Ommission of K+ from the medium caused hyperpolairzation of the tumor cells, but the trans-membrane potentials did not reach the values of hyperpolarized non-tumor cells. ACTH, added to the K+-free medium, caused little or no change in membrane potential of tumor cells except in one case of a virilizing adenoma, which responded very much like non-tumor tissue. Except for the virilizing adenoma, tumor tissue slices produced little or no detectable fluorogenic steroid, even in the presence of large amounts of ACTH or cyclic AMP. The virilizing adenoma responded with increased steroidogensis to ACTH and cyclic AMP.