摘要：The action of various metals on calcium metabolism is described in this review. Some metals have a toxic effect on calcium metabolism and its related bone metabolism in mammalian systems. Especially, lead induces hepatic calcium accumulation that is not caused by other heavy metals. This mechanism is based on the action that lead stimulates the mobilization of calcium into blood from bone ; thus lead-induced hypercalcemia stimulates secretion of calcitonin, and hormone causes accumulation of calcium into liver cells. Tin induces calcium accumulation in renal cortex, due to the action that tin increases calcium-binding protein in the cytosol and inhibits Ca-ATPase in the plasma membrane. Such phenomenon is not observed in other metals. Moreover, tin inhibits intestinal calcium transport and increases bile calcium excretion, resulting in hypocalcemia. Zinc produces hypocalcemia, based on the stimulation of gastric calcium secretion mediated through the action of acetylcholine, and the hypocalcemia induces bone resorption related to parathyroid hormone. Cadmium inhibits the stimulation of intestinal calcium transport due to 1, 25-dihydroxy vitamin D3. Also, cadmium directly causes both prevention of bone calcification and stimulation of bone resorption. On the other hand, aluminium is accumulated into bone and reveals a porotic effect. Lithium or manganese causes hypercalcemia. Copper inhibits bone resorption. However, the mechanism of action of these metals is not clarified. Thus action of metals is important as the toxic effect of metals, since disorder of calcium metabolism affects on some physiological functions.
