[Effect of 24,25-dihydroxycholecalciferol on chemical composition of the rat bone tissue during hypokinesia].

Severe hypokinesia in rats, maintained on rations with the Ca:P ratios from 1:0,5 to 1:3, was accompanied by hypocalcemia, osteoporosis and a slight increase in kidney carcinosis. Decrease in phosphorus consumption (Ca:P = 1:0,5 - 1:1) enabled to prevent these impairments in the intact animals and led to an increase in the rate of bone tissue mineralization in hypokinesia. An excessive utilization of phosphorus (Ca:P = 1:3) caused hypocalcemia, hyperphosphatemia and a slight osteoporotic destructions in bone tissue of intact animals increasing the severity of these impairments in hypokinesia. 24,25-Dihydroxycalciferol (24,25 (OH)2D3) at a daily dose 1.25 micrograms per an animal inhibited the osteoporotic destructions, stimulating mineralization of the diaphyses and epiphyses and corrected the hypocalcemia in rats under conditions of hypokinesia. 24,25 (OH)2D3 at the dose used did not increase nephrocalcinosis as well as did not exhibit a toxic effect, estimated in hypokinetic rats by alteration in body mass.