Tumor promoters potentiate the adrenomedullary secretion induced by acetylcholine and excess K possibly by stimulating phorbol ester receptors.

Catecholamine secretion from the perfused cat adrenal in response to 15 mM KC1 or acetylcholine was significantly increased by treatment with active tumor promoters. A good correlation was found between potentiation of the secretory response and the phorbol ester receptor binding activity, suggesting that promoters modulate the secretory mechanism via the receptors.