Chromaffin cell depolarization results in modulation of corticosteroidogenesis in co-culture

Previous morphological and physiological evidence indicates that the adrenal medulla can modulate adrenocortical steroidogenesis, most likely via paracrine or neuronal interactions. To study directly chromaffin-adrenocortical cellular interactions, we previously developed co-cultures of frog (Rana pipiens) adrenal (interrenal) cells. Importantly, chromaffin cells in these co-cultures extend processes that project toward or onto adrenocortical cells, thereby providing the substrate for direct autonomic regulation of adrenocortical function and also mimicking the organization in vivo. To test whether chromaffin cells in our co-cultures affect adrenocortical steroidogenesis, we used veratridine, a sodium ionophore, to depolarize chromaffin cells. Chronic veratridine (50 microM) results in increased corticosterone secretion on days 3 (950%), and 4 (350%). These results indicate that chromaffin cell activation results in the modulation of corticosteroidogenesis.