In vitro hydroxylation of vitamin D3 and 25-hydroxy vitamin D3 in tissues of Atlantic salmon Salmo salar, Atlantic mackerel Scomber scombrus, Atlantic halibut Hippoglossus hippoglossus and Atlantic cod Gadus morhua |
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| Authors: | GRAFF LIE & AKSNES |
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| Institution: | Institute of Nutrition, Directorate of Fisheries, Bergen, Norway; Department of Pediatrics, Haukeland Sykehus, Norway |
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| Abstract: | The in vitro metabolism of 14CD3 and 3H25OHD3 was investigated in different tissues from Atlantic salmon Salmo salar , Atlantic mackerel Scomber scombrus , Atlantic halibut Hippoglossus hippoglossus and Atlantic cod Gadus morhua . The tissues analysed were liver, kidney, head kidney, gills, spleen and intestine. The metabolites were extracted in methanol–chloroform and separated by normal-phase high-pressure liquid chromatography (HPLC) followed by scintillation counting. Identification of the metabolites was by comigration with standards on normal and reversed-phase HPLC systems and by protein-binding assays. All tissues from all species analysed produced hydroxylated derivatives identified as 25OHD3, 24,25(OH)2D3 and 1,25(OH)2D3. In addition, some unidentified derivatives were recorded, one probably being 25,26(OH)2D3. Organs producing great amounts of one metabolite also produced considerable amounts of the other possible derivatives, suggesting a lower degree of specificity in fish organs than in human organs. The predominating metabolite was 24,25(OH)2D3 in all organs from salmon and mackerel during incubation with 14CD3 and within most organs from all species during 3H25OHD3 incubation. The latter observation probably results from the need for decreasing rather than increasing the calcium absorption in these species, which live at least some periods of life in a marine environment. |
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| Keywords: | calcitriol calcium fish hydroxylation metabolites vitamin D3 |
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