Mechanisms of cadmium- and barium-induced adrenal catecholamine release
Shanbaky, I.O.; Borowitz, J.L.; Kessler, W.V.
Toxicology and Applied Pharmacology 44(1): 99-105
1978
ISSN/ISBN: 0041-008X PMID: 675697 Document Number: 128584
Different patterns of catecholamine release are produced by perfusion of isolated bovine adrenals with Cd2+, Ba2+ and Zn2+ (5 mM). The action of Zn2+ is weak but prolonged. The effect of Cd2+ is slow in onset and prolonged in duration compared to that of Ba2+. Neither Cd2+ nor Ba2+ increased release of the cytoplasmic enzyme, lactate dehydrogenase. These ions, therefore, do not disrupt adrenomedullary cells to cause catecholamine release. Neither Ba2+ nor Zn2+ affected 45Ca distribution in subcellular fractions of adrenal medulla. Cd2+, however, decreased mitochondrial and increased microsomal and supernatant 45Ca2+ contents. Mitochondria accumulated relatively large quantities of both Cd and Ba, but chromaffin granules contained twice as much Cd as Ba. Zn contents were relatively low in all subcellular fractions. Cd2+ probably releases adrenal amines by mobilizing mitochondrial Ca and possibly by a direct effect on chromaffin granules. Ba2+ does not affect the distribution of adrenomedullary cell Ca, but it probably mimics the action of Ca2+ in evoking catecholamine release. The weak effect of Zn2+ may be related to limited penetration of cells of adrenal medulla.