Stable isotope labeling of lead compartments in rats with ultralow lead concentrations.
Stable isotope labeling of lead compartments in rats with ultralow lead concentrations.
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超低铅浓度大鼠铅室的稳定同位素标记。
DOI：
10.1016/s0013-9351(05)80079-9
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发表时间：
1992
影响因子：
8.3
通讯作者：
Flegal,AR
中科院分区：
文献类型：
--
作者：
Smith,DR;Osterloh,JD;Niemeyer,S;Flegal,AR
哺乳动物骨骼作为内源性铅源的作用尚不清楚。这部分是由于在区分动员的骨骼铅从其他内源性和外源性铅来源的困难。因此，我们应用超净稳定的铅同位素技术来标记骨骼和软组织铅车厢内的大鼠可区分的铅同位素签名。雌性Wistar（限定植物群）大鼠被喂食富含206 Pb的饮用水（[Pb] = 110 ng/ml）并在持续2、4、7和14天后被处死。血液，肾脏，椎骨和胫骨组织进行了分析铅浓度和稳定同位素组成。暴露于206 Pb示踪剂2天后，软组织（血液和肾脏）和骨骼（椎骨和胫骨）组织中的同位素比值相差约40%。暴露10天后，超过90%的示踪剂同位素特征包含在软组织中，而骨骼组织在研究结束时仅获得约50%的示踪剂。由于这些动物是在无痕量金属的条件下饲养的，它们的全血（0.3-3纳克/克）、肾（11-27纳克/克干重）和骨（35-70纳克/克干重）组织中的铅浓度是已知的当代陆生哺乳动物中最低的，而且它们（骨中）的铅浓度与工业化前哺乳动物的水平相当。肾脏（鲜重）中铅浓度相对于血液中铅浓度的升高与极低暴露水平下肾脏中存在特定铅结合位点相一致。
The role of the mammalian skeleton as an endogenous lead source is unclear. This is due in part to difficulties in distinguishing mobilized skeletal lead from other endogenous and exogenous lead sources. Therefore, we have applied ultraclean stable lead isotope techniques to label skeletal and soft tissue lead compartments within the rat with distinguishable lead isotopic signatures. Female Wistar (defined flora) rats were fed206Pb-enriched drinking water ([Pb] = 110 ng/ml) and sacrificed after durations of 2, 4, 7, and 14 days. Blood, kidney, vertebra, and tibia tissues were analyzed for lead concentrations and stable isotopic compositions. The resulting isotopic ratios in soft (blood and kidney) and skeletal (vertebrae and tibia) tissues differed by ∼40% after 2 days exposure to the206Pb tracer. More than 90% of the tracer isotopic signature was contained in the soft tissues after 10 days exposure, while skeletal tissues acquired only ∼50% of the tracer by the end of the study. Because these animals were maintained under trace metal-clean conditions, they contained lead concentrations in whole blood (0.3–3 ng/g), kidney (11–27 ng/g dry wt), and bone (35–70 ng/g dry wt) tissues that are the lowest known reported for contemporary terrestrial mammals, and they (in bone) are comparable to levels in preindustrial mammals. The elevated concentrations of lead in kidney (fresh weight) relative to levels in blood are consistent with the presence of specific lead-binding sites in the kidney at very low levels of exposure.