RESTRICTED UPTAKE OF DIETARY COENZYME-Q IS IN CONTRAST TO THE UNRESTRICTED UPTAKE OF ALPHA-TOCOPHEROL INTO RAT ORGANS AND CELLS

The dietary uptake of alpha-tocopherol and coenzyme Q was investigated in rats. Rats were fed diets supplemented with alpha-tocopherol or co enzyme Q(10) (1 g/kg diet) or an unsupplemented control diet. In contr ol rat tissues, the content of coenzyme Q was 4-11 times higher than t hat of alpha-tocopherol, but in plasma, the ratio was reversed. Among the subcellular fractions of rat liver homogenate, Golgi vesicles and lysosomes had the highest alpha-tocopherol concentration, and high con centrations of coenzyme Q were observed in the outer and inner mitocho ndrial membranes as well as in lysosomes, Golgi vesicles and plasma me mbranes. The uptake of alpha-tocopherol into the liver and plasma reac hed a maximal level after only 2 d of supplementation, whereas in the kidney, heart, muscle and brain, the levels continued to increase thro ughout the 6-wk treatment period. In contrast, dietary coenzyme Q was taken up into the liver and plasma only, and not into the other organs . This lipid appeared mainly in the Golgi system, whereas cy-tocophero l exhibited a more general cellular distribution. The decay of the sup plied alpha-tocopherol was slow in the various organs, but the disappe arance of coenzyme Q was rapid from both liver and plasma. Pretreatmen t of rats with alpha-tocopherol increased the levels of both endogenou s and exogenous coenzyme Q in the liver and plasma. These results demo nstrate that the uptake of alpha-tocopherol from the diet is an extens ive and general phenomenon at both the tissue and cellular levels, in contrast to the selective and restricted uptake of coenzyme Q.