Basal catecholamine and cortisol secretion in primary chromaffin cell cultures before and after purification and retroviral transfection

We have investigated the effects of supraphysiological concentrations of ca techolamines on glucocorticoid secretion in vitro. These effects were analy zed in adrenocortical cells shown to be present in chromaffin cell cultures as well as in cortical cells cocultured with transfected chromaffin cells that overproduce catecholamines. Cortisol release from residual cortical ce lls in chromaffin cell cultures was found to be 2.5 times higher than from isolated adrenocortical cells. Removal of the adrenocortical cells from the chromaffin cells resulted in an almost complete cessation of cortisol secr etion. Catecholamine overproduction was achieved by transfecting chromaffin cells with the blank retroviral vector pSAM-EN. Coculture of adrenocortica l cells with these transfected chromaffin cells further enhanced the stimul ating effect of chromaffin cells on cortisol 2.3-fold compared to normal co cultures. In conclusion, cortical cells in chromaffin cell cultures secrete significant amounts of cortisol, which should be considered when evaluatin g the endocrine function of these cell cultures and which can be abolished by purification. The hormonal activity of adrenocortical cells is highly in creased in an environment of catecholamine overproduction, which is of both basic and clinical importance.