Shanbaky N M, Emran A, Maickel R P, Borowitz J L
Res Commun Chem Pathol Pharmacol. 1982 Mar;35(3):443-53.
To examine the possibility that enhanced uptake of Ba2+ and Cd2+ might explain the increased secretion induced by these metals at high pH, Ba2+ and Cd2+ were perfused through isolated bovine adrenals at high pH 7.4 and 8.3. Both metals were found in greater concentrations in the tissue after exposure at the high pH. Continued perfusion of adrenals with Locke's solution at pH 7.4 or 8.3 after exposure to the metals showed that Cd remaining in the tissue was not affected by the pH of the washout but residual Ba was greater after washout at the high pH. Catecholamine release was correlated with tissue Ba content regardless of the pH of the washout, but residual Cd was not correlated with amine secretion. It appears that low H+ concentrations increase influx of Ba2+ and Cd2+ into adrenomedullary cells and decrease efflux of Ba from this tissue. Elevated intracellular levels of Ba and Cd probably mediate the enhanced adrenomedullary secretion noted after exposure to the metals at high pH. Barium in the tissue is proportional to secretion, but it appears that only part of the Cd2+ entering the cells is involved in initiating adrenal catecholamine release.
为了研究Ba2+和Cd2+摄取增加是否可以解释这些金属在高pH值时诱导的分泌增加，在高pH值7.4和8.3下，将Ba2+和Cd2+灌注通过分离的牛肾上腺。在高pH值暴露后，在组织中发现这两种金属的浓度更高。在暴露于金属后，用pH值为7.4或8.3的洛克溶液继续灌注肾上腺，结果显示，组织中残留的Cd不受洗脱液pH值的影响，但在高pH值洗脱后，残留的Ba更多。无论洗脱液的pH值如何，儿茶酚胺释放与组织Ba含量相关，但残留的Cd与胺分泌不相关。似乎低H+浓度会增加Ba2+和Cd2+流入肾上腺髓质细胞，并减少Ba从该组织的流出。暴露于高pH值的金属后，细胞内Ba和Cd水平升高可能介导了肾上腺髓质分泌增强。组织中的Ba与分泌成正比，但似乎只有部分进入细胞的Cd2+参与启动肾上腺儿茶酚胺释放。
