Sato K, Kusaka Y, Zhang Q, Deguchi Y, Li B, Okada K, Nakakuki K, Muraoka R
Department of Environmental Health, Fukui Medical School, Japan.
Ind Health. 1997 Oct;35(4):456-60. doi: 10.2486/indhealth.35.456.
Occupational exposure to mercury has long been associated with renal proximal injury and an increased incidence of proteinuria, as has such exposure to cadmium. Renal citrate excretion is very important with respect to acid-base balance since the metabolism of citrate generates three bicarbonate ions. In this study, we exposed isolated rat renal brush border membrane vesicles (BBMV) to mercury (Hg2+) and examined their citrate uptake characteristics. BBMV were prepared by the divalent cation precipitation method. Citrate uptake was measured by the Millipore rapid membrane filtration method. The preincubation of BBMV with 0.5 and 2 mM HgCl2 for 1 min significantly inhibited citrate uptake compared with that of BBMV without Hg preincubation. The analysis of the time course of citrate uptake during a 30-min preincubation of BBMV with 0.1 mM Hg2+ also revealed a significant reduction in the uptake compared with that of the control BBMV without preincubation. These findings indicate that the preincubation of BBMV with mercury results in a time- and concentration-dependent inhibition of citrate uptake.
长期以来，职业性汞暴露一直与近端肾小管损伤及蛋白尿发病率增加有关，镉暴露也是如此。肾柠檬酸排泄对于酸碱平衡非常重要，因为柠檬酸代谢会产生三个碳酸氢根离子。在本研究中，我们将分离的大鼠肾刷状缘膜囊泡（BBMV）暴露于汞（Hg2+）中，并检测其对柠檬酸的摄取特性。BBMV采用二价阳离子沉淀法制备。柠檬酸摄取通过密理博快速膜过滤法测定。与未预先用汞处理的BBMV相比，用0.5 mM和2 mM HgCl2对BBMV进行1分钟的预孵育显著抑制了柠檬酸摄取。在对BBMV用0.1 mM Hg2+进行30分钟预孵育期间对柠檬酸摄取时间进程的分析也显示，与未预孵育的对照BBMV相比，摄取量显著降低。这些发现表明，用汞对BBMV进行预孵育会导致对柠檬酸摄取的时间和浓度依赖性抑制。
