Importance of the kidneys in metabolism of vitamins A1 and A2 and their fatty acyl esters in mink feeding on fish-based diets and exposed to Aroclor 1242

Two-month-old female mink (Mustela vison) were fed diets based on freshwater smelt (Osmerus eperlanus), Baltic herring (Clupea harengus membras), or North-Atlantic herring (Clupea harengus harengus) for 21 weeks. Half of the smelt-fed mink were exposed to the commercial polychlorinated biphenyl (PCB) preparation Aroclor 1242 (1 mg/day) in the feed. Retinol (vitamin A(1)), 3,4-didehydroretinol (vitamin A(2)), their fatty acyl esters, and vitamin E were studied in the kidneys by reversed-phase high-performance liquid chromatography. Exposure to Aroclor 1242 resulted a significant decrease in the alcoholic and esterified vitamin A(2). Levels of the A(1) analogs did not change due to the PCBs and were the same in mink fed either smelt or Baltic herring. In mink fed very fatty Atlantic herring, the renal levels of vitamin A(1) and E were significantly lower than in the other mink and apparently consumed by lipid peroxidation. The vitamins were located mainly in the cortex, and the fatty acyl esters showed a fatty acid composition that differed from those in liver and plasma. In the kidneys of the smelt-fed mink (control or Aroclor-exposed) the ratio of vitamin A(2) to A(1) was much lower than the ratios in the liver or plasma, suggesting inefficient uptake of A(2) in the kidneys. In the PCB-exposed mink, in which vitamin losses are increased, tissue levels of vitamin A(2) may be more difficult to maintain than levels of vitamin A(1) (C) 2003 Elsevier Science (USA). All rights reserved.