Alexander J, Aaseth J, Norseth T
Toxicology. 1982;24(2):115-22. doi: 10.1016/0300-483x(82)90050-6.
Isolated rat liver mitochondria rapidly accumulate chromate (1.2 microM 51CrO4(2-)) to about 0.25-0.30 nmol Cr/mg protein. The relative uptake decreases with increasing chromate doses. Chromate uptake decreases when pH is raised from 7.0 to 7.5.N-ethylmaleimide (0.25 mM) and butylmalonate (5 mM) inhibit chromate uptake to 70% and 30% of control values, respectively, whereas mersalyl (40 nmol/mg protein) causes an inhibition of greater than 95%. Both sulphate and phosphate decrease mitochondrial chromate uptake, the former being more effective in lower doses (5 mM). These results indicate that transport of chromate is mediated both on the dicarboxylate and the phosphate carrier. The extensive mitochondrial chromium accumulation can be explained by trapping of chromium, probably by reduction of chromate to the trivalent form, within the mitochondria. Release of chromium after chromate loading was seen after 15 min. Added after chromate loading, mersalyl partly prevents this release. Trivalent chromium as 51CrCl3 is taken up to a much lower degree than hexavalent chromium as 51CrO4(2-). The presence of glutathione (5 mM) reduces the uptake both of 51Cr-III and 51Cr-VI, indicating extramitochondrial reduction of Cr-VI to Cr-III and subsequent binding to GSH.
分离出的大鼠肝脏线粒体可迅速积累铬酸盐（1.2微摩尔51CrO4(2-)），积累量可达约0.25 - 0.30纳摩尔铬/毫克蛋白质。相对摄取量随铬酸盐剂量增加而降低。当pH从7.0升至7.5时，铬酸盐摄取量减少。N - 乙基马来酰亚胺（0.25毫摩尔）和丁基丙二酸酯（5毫摩尔）分别将铬酸盐摄取抑制至对照值的70%和30%，而汞撒利（40纳摩尔/毫克蛋白质）的抑制率大于95%。硫酸盐和磷酸盐均会降低线粒体对铬酸盐的摄取，前者在较低剂量（5毫摩尔）时更有效。这些结果表明，铬酸盐的转运是由二羧酸载体和磷酸盐载体介导的。线粒体中大量的铬积累可能是由于铬在被捕获，可能是通过将铬酸盐还原为三价形式，在线粒体内实现的。铬酸盐加载后15分钟可见铬的释放。在铬酸盐加载后添加汞撒利可部分阻止这种释放。三价铬以51CrCl3形式的摄取程度远低于六价铬以51CrO4(2-)形式的摄取程度。谷胱甘肽（5毫摩尔）的存在会降低51Cr - III和51Cr - VI的摄取，这表明线粒体外将Cr - VI还原为Cr - III并随后与谷胱甘肽结合。
