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Journal archive > 2010 > N 2 March-April

FEATURES OF CHOLECALCIFEROL HYDROXYLATION PROCESS IN?THE LIVER OF RATS
UNDER D-HYPERVITAMINOSIS CONDITIONS AND ACTIONS OF ?-TOCOPHEROL

M. M. Veliky, L. I. Apukhovska, V.?M.?Vasylevska, O. Ju. Lototska, A.I.Bezusiak, A. V. Chomenko

Palladin Institute of Biochemistry, National Academy of Sciences of Ukraine, Kyiv;
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It is shown, that hepatocytes contain two (microsomal and mitochondrial) vitamin D3 25-hydroxylase enzymes, which differ as to their activity and function with maximal activity at different concentrations to substrate, namely at 15 ?M and 100?µM of vitamin D3, accordingly.
Activity of vitamin D3 25-hydroxylase enzymes of hepatocytes is regulated by cholecalcife­rol and ?-tocopherol. The general and microsomal vitamin D3 25-hydroxylase enzymes activity of hepatocytes is lowered, but mitochondrial isoform is increased under D-hypervitaminosis conditions. Vitamin E increases microsomal vitamin D3 25-hydroxylase activity and decreases mitochondrial isoform activity of rats hepatocytes under D-hypervitaminosis conditions.
It is established that D-hypervitaminosis is accompanied by expressed hypercalcemia and hyperphosphatemia, by decreased contents of mine­ral components in the bone tissue and high activity of alkaline phosphatase in the blood serum. The physiological doses of vitamin E under these conditions normalized the mineral metabolism, contents of calcium, phosphates and activity of alkaline phosphatase isoform in the blood serum.

Key words: 25OHD3 content, vitamin D3 25-hydroxylase enzymes activity, vitamin D3, vitamin E, D-hypervitaminosis, mineral metabolism.

The original article in Ukrainian is available for download in PDF format.

© The Ukrainian Biochemical Journal