ERYTHROCYTE-MEMBRANE FLUIDITY AND TISSUE LIPID PEROXIDES IN FEMALE GUINEA-PIGS ON GRADED VITAMIN-C INTAKE

The effect of low (1 mg/animal/day), medium (10 mg/animal/day) and hig h (100 mg/animal/day) intake of ascorbic acid on tissue lipid peroxida tion (LPO) and the physical state of erythrocyte membranes was investi gated in female guinea-pigs fed a vitamin E low diet. Animals were kil led after 9-11 weeks and the blood, liver, lungs, kidneys and adrenals were analysed. The LPO was estimated by the determination of malondia ldehyde with HPLC. The physical state of erythrocyte membranes was det ermined spectrofluorometrically and expressed as fluorescence polariza tion of membrane lipid specific probe 1,6-diphenyl-1,3,5-hexatriene. T he LPO concentrations in the liver and adrenals of the group on a low vitamin C intake were significantly increased. A significant non-linea r negative correlation between C vitamin levels and LPO concentrations was found in these tissues. The fluidity of erythrocyte membranes as a measure of their structural state was significantly lower in the gro up with a low intake of C vitamin. It is probable that the water-solub le antioxidants, such as vitamin C, act in the plasma as primary defen se against oxidative stress if the radicals are formed initially in th e aqueous phase of whole blood.