[Calcium metabolism and the level of active metabolites of vitamin D3 in the rat serum during bone regeneration].

Fracture of rat femur bone was accompanied by an increase in content of calcium and 25(OH)D3, by a decrease in content of 1,25(OH)2D3 while the 24,25(OH)2D3 level was unaltered in blood serum as well as an augmented absorption of calcium was found in small intestine during formation and mineralization of callus. The elevated consumption of the vitamin D3 active metabolites in small intestine mucose and in bone tissue and/or stimulation of their biosynthesis in these tissues appear to occur in response to transformation of the calcium metabolism and to remodelation of rat bone tissue in fractures.