Availability of Adipose Tissue Tocopherol in the Guinea Pig

Abstract

Young guinea pigs were fed a purified diet containing vitamin E for 3 weeks and then fed the diet without vitamin E for 8 weeks. Levels of vitamin E in plasma and liver decreased to low values within a week. Depletion rates for heart and muscle were much slower, whereas the rate of loss from fat was negligible. In experiments with more mature guinea pigs and a depletion period of 4 months, the depletion rate of tocopherol from fat was also barely detectable. Both yound and mature guinea pigs developed myopathy after 8 weeks of depletion. Apparently, tocopherol in adipose tissue is not sufficiently available to maintain plasma tocopherol levels or to prevent signs of vitamin E deficiency. Even during fasting, adipose tissue tocopherol was not mobilized readily. During a 4 day fast, adipose tissue mass diminished considerably, but there was no appreciable loss of tocopherol.

Sensitivity of respiratory chain activities to lipid peroxidation: effect of vitamin E deficiency

“…The fact that these tissues along with testes generally have lower levels of vitamin E than spleen, liver, lung and heart [31], may make them more vulnerable to loss of vitamin E in the diet. However, this contrasts with the higher rate of vitamin E loss from the liver and spleen in comparison with the heart, skeletal muscle and brain in the absence of dietary vitamin E [32,33]. The decreased activity of complex IV and complex I in the vitamin E-deficient rat muscle mitochondria is in agreement with that published previously [4].…”

Clinical Evaluation of Alpha-Tocopherol in Buccal Mucosal Cells of Children

“…The RBC tocopherol level was concomitantly lower in the hyperlipemic group than in the normolipemic group (p<0.01), as reported in our previous paper (12). This finding appears to confirm the concept that increased lipid pools in the body, including adiposity and hyperlipemia, can act as a relatively nonexchangeable depot for tocopherol and can drastically affect its uptake by other tissues, possibly as a result of competition between the excess amounts of lipids in plasma and adipose tissue and the membrane lipids of other tissues (20,21). We have previously studied RBC and platelet tocopherol levels as an index of vitamin E status (8,9,12,15).…”

Tocopherol level in human blood cells.

“…It also derives from the additional finding (17) that RBC content of tocopherol decreased as plasma lipid increased when the distribution of isotope-labeled tocopherol in the in vitro reaction system between the plasma, which was experimentally made on hypo and hyperlipemia, and RBC was examined. The recent report by MACHLIN (19) may reflect Bieri's view, that in a guinea pig alternately fed a diet with and without vitamin E histological evidence of a vitamin E deficiency (myopathy) appeared at the time when adipose tocopherol stores were not significantly different from the initial values. These findings suggest that the various lipid pools in the body act as a "sink" for tocopherol and can drastically affect how the various nonlipid tissues take up the vitamin.…”