Abstract
Effects of dietary addition of some xenobiotics on the metabolism of α-tocopherol in rats were studied with special reference to cholesterol metabolism. Dietary xenobiotics including PCB, DDT, Chloretone, phenobarbital, etc. caused an increase in serum α-tocopherol and cholesterol. The effects of dietary PCB on serum and tissue levels of α-tocopherol were influenced with dietary protein and copper. The increases in serum α-tocopherol and cholesterol due to the chemicals were attributed to the increases in the fraction of high-density-lipoproteins (HDL). Dietary PCB and Chloretone caused an increase in apparent absorption of α-tocopherol. Dietary clofibrate depressed the increases in serum and tissue α-tocopherol, and serum cholesterol and also suppressed the increase in apparent absorption of α-tocopherol by Chloretone. These results suggest that the increase in serum cholesterol due to xenobiotics relates to the increase in serum and tissue α-tocopherol. As well as xenobiotics, feeding of cystine excess and histidine excess diets which are known to cause hypercholesterolemia also increased serum α-tocopherol.
