L. I. Apukhovska, M. M. Veliky, O. Ju. Lototska, A. V. Chomenko
Palladin Institute of Biochemistry, National Academy of Sciences of Ukraine, Kyiv;
It is established, that dose-dependent influence of vitamin E on vitamin D3 metabolism, is conditioned by degree of cholecalciferol sufficiency. Under a condition of D-hypovitaminosis, contents of 25ОНD3 in blood serum is 2-fold reduced and vitamin D3 25-hydroxylase enzymes activity increased in rat hepatocytes. Vitamin E (0.726–7.26 IU) significantly stimulated the effect of vitamin D3 (40? IU) in animals with D-hypovitaminosis and led to further increase of 25OHD3 content in the blood serum and activity of vitamin?D3 25-hydroxylase enzymes in hepatocytes. In D-hypervitaminosis the contents of 25ОНD3 in blood serum was more than 3-fold increased and vitamin D3 25-hydroxylase enzymes activity was inhibited. Vitamin E (0,726–7,26 IU) lowered the vitamin D toxicity, decreased contents of 25OHD3 in blood serum and activity of vitamin D3 25-hydroxylase enzymes in hepatocytes.
High doses of vitamin E (36.3 IU) under these conditions demonstrated negative effect on vitamin D3 metabolism. The mechanism of vitamin E participation in the vitamin D3 metabolism under D hypovitaminosis and D-hypervitaminosis may be its influence on the activity of different vitamin D3 25-hydroxylase systems of hepatocytes.
Key words: vitamin D3, vitamin E, 25OHD3 content, vitamin D3 25-hydroxylase activity, D-hypovitaminosis, D-hypervitaminosis.
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