Mechanism of secretion from the adrenal medulla. II. Release of catecholamines and storage vesicle protein in response to chemical stimulation.

Abstract

The release of catecholamines and a specific protein of the storage vesicles was meas-ured in isolated perfused bovine adrenal glands. Stimulation of catecholamine secretion by acetylcholine, nicotine, or Ba caused a parallel increase in the secretion of the stor-age vesicle protein. The ratio of catecholamines: vesicle protein in the perfusates was, within the limits of experimental error, the same as that in the intact gland. The re-lease of both the vesicle protein and the catecholamines required Ca and was temper-ature dependent. These studies provide additional evidence to support the hypothesis that catecholamines are secreted from the medulla by a process in which the storage vesicle contents are released directly to the exterior of the cell.