Kato Y, Takimoto S, Ogura H
Calcif Tissue Res. 1977 Dec 14;24(1):41-6. doi: 10.1007/BF02223295.
The present study is an investigation of the mechanism of hypercalcemia and hyperphosphatemia induced by the intravenous injection of lead acetate (Pb-Ac). A total of 118 male rats were injected with 30 mg/kg of Pb-Ac, or with 16.5 mg/kg of sodium acetate as the control. The levels of serum calcium, phosphorus and lead were then determined at various time periods after the injections. Serum calcium and phosphorus levels increased with time after Pb-Ac injection and the maximum values of calcium (17 mg%) were found after 1 h and of phosphorus (13.5 mg%) after 30 min. Both calcium and phosphorus levels reverted to the normal range after 12 h. The maximum net rates of increase of calcium and phosphorus were found immediately after Pb-Ac injection. At that time, deposition of lead at the calcifying sites of bone and incisor dentin was demonstrated by a histochemical examination. In other experiments the changes in the calcium and phosphorus contents in the medium after shaking bone powder in serum with Pb-Ac in an in vitro system were studied. It was confirmed that the calcium and phosphorus were displaced from the bone mineral, the extent of the displacement being correlated with the concentration of the Pb-Ac added to the medium, and that these displacements were very rapid reactions. These results suggest that hypercalcemia and hyperphosphatemia following Pb-Ac injection results from a direct action of lead on the bone mineral.
本研究旨在探讨静脉注射醋酸铅（Pb-Ac）所致高钙血症和高磷血症的机制。将118只雄性大鼠注射30mg/kg的Pb-Ac，或注射16.5mg/kg的醋酸钠作为对照。然后在注射后的不同时间段测定血清钙、磷和铅的水平。注射Pb-Ac后，血清钙和磷水平随时间升高，钙的最高值（17mg%）在1小时后出现，磷的最高值（13.5mg%）在30分钟后出现。12小时后钙和磷水平均恢复至正常范围。钙和磷的最大净增加率在注射Pb-Ac后立即出现。此时，通过组织化学检查证实铅沉积在骨和切牙牙本质的钙化部位。在其他实验中，研究了在体外系统中用含Pb-Ac的血清振荡骨粉后培养基中钙和磷含量的变化。证实钙和磷从骨矿物质中被置换出来，置换程度与添加到培养基中的Pb-Ac浓度相关，并且这些置换是非常快速的反应。这些结果表明，注射Pb-Ac后出现的高钙血症和高磷血症是由于铅对骨矿物质的直接作用所致。
