Xie Y, Chiba M, Shinohara A, Watanabe H, Inaba Y
Department of Epidemiology and Environmental Health, Juntendo University School of Medicine, Tokyo, Japan.
Ind Health. 1998 Jul;36(3):234-9. doi: 10.2486/indhealth.36.234.
To clarify the function of Pb-binding protein and the interaction between lead and selenium in human erythrocytes, the following experiments were performed. (a) blood from a man who has not been exposed to lead occupationally, (b) blood from lead-exposed workers and (c) blood from control subjects working in the same plant were used. (a) was incubated with Pb and/or Se. Hemolysates of rinsed erythrocytes were applied onto a Bio-gel A 1.5 m column and eluted by 40 mM Tris-HCl buffer (pH 7.0). As the results, (1) Pb in erythrocytes was found in ALAD fraction. When Pb was added in vitro at 1.25 microM of final concentration, Pb content of ALAD fraction increased and the other Pb-containing fraction appeared at the position of a smaller molecular size than that of Hb fraction. When Pb dose added was increased to 2.5 or 10 microM, Pb contents in the newly appeared fraction was larger than that in ALAD fraction. The affinity of Pb with the protein in the new fraction was weak, and Pb was released from the protein by ultrafiltration. (2) There were main and sub-peaks containing Pb in erythrocytes from Pb-workers; the former was ALAD fraction and the others were smaller molecules than ALAD. The peak of Pb observed with the blood from a worker who has worked at the same plant for more than 20 years (chronic exposure) corresponded with the new peak which appeared in vitro Pb exposure. (3) As to the interaction between Pb and Se, there was no effect of Se added in vitro on the position of Pb-containing fraction and on Pb amounts in the chromatographic profile. When Se was incubated with blood, however, coexistence of Pb made Se concentration in erythrocytes high compared with the case of Se alone.
为阐明人红细胞中铅结合蛋白的功能以及铅与硒之间的相互作用，进行了以下实验。使用了以下几种血液：(a) 来自未接触过职业性铅暴露的男性的血液；(b) 来自铅暴露工人的血液；(c) 来自同一工厂工作的对照受试者的血液。将(a)与铅和/或硒一起孵育。将冲洗过的红细胞的溶血产物应用于Bio - gel A 1.5 m柱，并用40 mM Tris - HCl缓冲液（pH 7.0）洗脱。结果如下：(1) 在红细胞中的铅存在于δ-氨基乙酰丙酸脱水酶（ALAD）组分中。当体外添加终浓度为1.25 μM的铅时，ALAD组分中的铅含量增加，并且另一个含铅组分出现在比血红蛋白（Hb）组分分子尺寸更小的位置。当添加的铅剂量增加到2.5或10 μM时，新出现组分中的铅含量大于ALAD组分中的铅含量。铅与新组分中蛋白质的亲和力较弱，并且通过超滤铅从蛋白质中释放出来。(2) 铅作业工人的红细胞中存在含铅的主峰和次峰；前者是ALAD组分，其他峰的分子比ALAD小。在同一工厂工作超过20年（长期暴露）的一名工人的血液中观察到的铅峰与体外铅暴露时出现的新峰相对应。(3) 关于铅与硒之间的相互作用，体外添加硒对含铅组分的位置和色谱图中的铅含量没有影响。然而，当硒与血液一起孵育时，与单独使用硒的情况相比，铅的共存使红细胞中的硒浓度升高。
