Secretion of Newly Taken-Up Ascorbic Acid by Adrenomedullary Chromaffin Cells

Primary cultures of bovine adrenomedullary cells accumulate carbon-14-labeled ascorbic acid through a saturable and energy-dependent process. The newly taken-up ascorbate is released concomitantly with catecholamines upon stimulation of chromaffin cell secretion. The release of ascorbate is Ca2+-dependent and mediated through activation of nicotinic receptors. These results indicate that exogenous ascorbate taken up into chromaffin cells is incorporated in situ into a secretable compartment, probably the catecholamine-containing chromaffin vesicles.