Rossi E, Costin K A, Garcia-Webb P
Department of Clinical Biochemistry, Queen Elizabeth II Medical Centre, Nedlands, Western Australia.
Clin Chem. 1990 Nov;36(11):1980-3.
Lead exposure is a well-known cause of increases in urinary coproporphyrin and erythrocyte zinc-protoporphyrin, so these compounds are often used to monitor occupational lead exposure. The increased concentrations are usually assumed to result from lead inhibition of two of the mitochondrial enzymes of heme biosynthesis, coproporphyrinogen oxidase (EC 1.3.3.3) and ferrochelatase (EC 4.99.1.1). We studied 88 subjects in whom the degree of occupational lead exposure was established by measuring erythrocyte lead and protoporphyrin. Assay of lymphocyte coproporphyrinogen oxidase and ferrochelatase activities showed that these enzymes were unaffected by lead exposure, as was a related enzyme, lymphocyte NADH-ferricyanide reductase. We propose alternative explanations for the increased concentrations of coproporphyrin and zinc-protoporphyrin seen in lead exposure.
铅暴露是导致尿中粪卟啉和红细胞锌原卟啉升高的一个众所周知的原因，因此这些化合物常被用于监测职业性铅暴露。浓度升高通常被认为是由于铅抑制了血红素生物合成的两种线粒体酶，即粪卟啉原氧化酶（EC 1.3.3.3）和亚铁螯合酶（EC 4.99.1.1）。我们研究了88名通过测量红细胞铅和原卟啉来确定职业性铅暴露程度的受试者。淋巴细胞粪卟啉原氧化酶和亚铁螯合酶活性的测定表明，这些酶不受铅暴露的影响，一种相关酶，淋巴细胞NADH-铁氰化物还原酶也是如此。我们对铅暴露时所见的粪卟啉和锌原卟啉浓度升高提出了其他解释。
