The metabolism of lead in isolated bone cell populations: interactions between lead and calcium.
The metabolism of lead in isolated bone cell populations: interactions between lead and calcium.
复制标题
分离的骨细胞群中铅的代谢：铅和钙之间的相互作用。
DOI：
10.1016/0041-008x(83)90049-2
复制
发表时间：
1983
影响因子：
3.8
通讯作者：
Rosen,JF
中科院分区：
文献类型：
--
作者：
Rosen,JF
以前在骨器官培养中的铅代谢研究已经部分地定义了一个可交换的骨铅室，该骨铅室由通常控制骨细胞代谢的相同离子和激素调节。本研究进行了进一步的特点，这一亚室的可交换的铅，并检查可能的铅和钙之间的相互作用，在孤立的骨细胞群。采用胶原酶连续消化法，从小鼠颅骨中分离出破骨细胞（OC）和成骨细胞（OB）。结果表明：（1）OC细胞对~（210）Pb的摄取迅速，且OC细胞对Pb的亲合力大于OB细胞;（2）当铅浓度从6.5 μm增加到65 μm时，OB细胞对Pb的摄取几乎没有增加，而OC细胞对Pb的摄取几乎呈线性，（3）OC电池负载~（210）Pb后，标记物明显释放，（4）生理浓度的甲状旁腺素（PTH）在培养5 min后，能显著增加OC细胞对~（210）Pb和~（45）Ca的摄取;随着Ca ~（2+）摄取量的显著降低，Pb在OC细胞中的蓄积持续进行。（5）PTH对~（210）Pb摄取量的影响在50 ~ 250 ng/ml范围内呈线性关系。（6）升高中浓度铅（~ 26 μm）显著增强OC细胞的Ca ~（2+）摄取，远高于生理浓度PTH所产生的水平。这些数据表明：（1）从数量上讲，在OC和OB细胞单层的体外系统中，OC细胞是铅代谢的主要细胞类型，（2）发生了铅介导的OC细胞掺入，可能涉及受激素刺激（如PTH）影响的膜通透性变化，（3）低浓度铅对细胞钙代谢的调节可能具有干扰依赖钙作为第二信使的不同组织的多种细胞功能的潜力。
Previous studies of lead metabolism in bone organ culture have defined, in part, an exchangeable bone lead compartment regulated by the same ions and hormones that normally control bone cell metabolism. This study was undertaken to further characterize this subcompartment of exchangeable lead and to examine possible interactions between lead and calcium in isolated bone cell populations. Bone cells, derived from mouse calvaria, were enriched for osteoclasts (OC) and osteoblasts (OB) by a sequential collagenase digestion. We found that (1) the uptake of210Pb by OC cells was rapid, and OC cells had greater avidity for lead, compared to OB cells, at concurrent time points of incubation, (2) OB cells showed very little increase in lead uptake as medium lead concentrations were increased from 6.5 to 65 μm, in contrast, the uptake of lead by OC cells was almost linear, (3) after loading OC cells with210Pb, significant release of label (∼ 15 to 30%) occurred within short time periods (≦2 hr) during incubations in chase medium, (4) parathyroid hormone (PTH) at physiological concentrations effected a marked increase in210Pb and45Ca uptake in OC cells, after 5 min of incubation, Pb accumulation into OC cells continued as calcium uptake markedly decreased, (5) this PTH effect on210Pb uptake was linear over PTH concentrations of 50 to 250 ng/ml, and (6) rising medium concentrations of lead (≧26 μm) markedly enhanced/exaggerated calcium uptake by OC cells, far above that produced by physiological concentrations of PTH. These data indicate that (1) quantitatively, OC cells are the predominant cell type in the metabolism of lead in this in vitro system of OC and OB cell monolayers, (2) mediated incorporation of lead into OC cells occurs and likely involves changes in membrane permeability effected by hormonal stimuli, such as PTH, and (3) modulations in cellular calcium metabolism induced by lead at low concentration may have the potential of disturbing multiple cell functions of different tissues that depend upon calcium as a second messenger.