Adrenal catecholamine release by trivalent metallic cations.

The order of effectiveness of trivalent metallic cations in releasing catecholamines from isolated perfused bovine adrenals is La greater than Ce greater than Pr greater than Nd. Other trivalent metals are essentially inactive in this system. A second exposure of the glands to trivalent metals causes little or no secretion. Omission of calcium from the perfusing medium decreases the response to La+3 or Ce+3. Trivalent metallic cations of a relatively narrow range of charge density appear to temporarily open a calcium gate which results in calcium influx and adrenomedullary catecholamine secretion.