[H3-25-hydroxycholecalciferol metabolism in rats with experimental femoral fractures]

At the 3d day after femoral bone fracture in rats, the concentration of 3H-25-OHD3 injected intraperitoneally 18 h before sacrifice was 25 and 60% higher in the kidneys and small intestinal mucosa, respectively, whereas the incorporation of the label in 1,25(OH)2D3 in the blood serum and small intestinal mucosa was 50 and 70% higher as compared with intact control. The binding of 3H-25-OHD3 in the diaphysis and epiphysis of the fractured bone was 2-3 times as increased at the 3d and 10th days after fracture. A similar but less marked increase in the accumulation of 3H-25-OHD3 was recorded in the paired intact bone of rats with femoral fractures. Incorporation of the label from 3H-25-OHD3 in 1,25(OH)2D3 and 24,25(OH)2D3 in the epiphyses of the fractured bone as well as in the epiphyses and diaphysis of the intact bone of rats with femoral fractures was 1.5-2 times as increased at all the times of the observation period (3, 10, 28 days after fracture).