Effect of essential trace metals on bone metabolism in weanling rats: comparison with zinc and other metals' actions.

The effect of essential trace metals on bone metabolism was investigated in the femoral diaphysis of weanling rats. Oral administration of zinc (1.53-306 mumol/100 g body weight) for 3 days produced significant increases in alkaline phosphatase activity and DNA content. These biochemical indices were also increased by oral administration of chromium (III), cobalt, copper, manganese, and nickel with the dose of 1.53 mumol/100 g. With the dose of 15.3 mumol/100 g of above all metals, except zinc, the enzyme activity was significantly decreased in comparison with control, while DNA content was not decreased significantly. Moreover, the effect of zinc on alkaline phosphatase activity and DNA content was not enhanced by simultaneous administration of other metals (1.53 mumol/100 g). The present study indicates that, of the essential trace metals, zinc can effectively stimulate the bone growth and calcification with comparatively higher dose levels. This suggests a nutritional significance of zinc on bone growth.