[Bone tissue collagen and vitamin D in chronic kidney insufficiency in rats]

Chronic kidney insufficiency, caused by subtotal nephrectomy, did not lead to distinct alterations in hydroxyproline concentration in blood and to its excretion in rats within 1-1.5 months after the operation. Content of salt-soluble collagen was decreased in diaphyses of rat tubular bones in chronic kidney insufficiency; in the epiphyses (with metaphyses) content of the collagen fraction was increased, but the concentration of non-soluble collagen was unaltered. Decrease in content of salt-soluble collagen in diaphyses in chronic kidney insufficiency was similar to that in experimental vitamin D deficiency. The decrease might be due to impairment in formation of the active form of vitamin D-1,25-dihydroxycholecalciferol. Other pathogenetic factors (effect of uremic toxins and stress) were apparently of primary importance for development of impairments of collagen metabolism in epiphyses. Dihydrotachysterol, the structural analogue of 1,25-dihydroxycholecalciferol, normalized the alterations in content of salt-soluble collagen in diaphyses and did not affect the impairments of collagen metabolism in epiphyses of rat bones in chronic kidney insufficiency.