INCREASED CALCIUM-INDEPENDENT PHOSPHOLIPASE A(2) ACTIVITY IN VITAMIN-E AND SELENIUM-DEFICIENT RAT LUNG, LIVER, AND SPLEEN CYTOSOL IS TIME-DEPENDENT AND REVERSIBLE

Long-Evans hooded rats maintained on vitamin E and selenium-deficient diets for 6 weeks from weaning exhibited a pattern of enhancement of c alcium-independent phospholipase A(2) activity in spleen cytosol simil ar to that previously reported for the lung and liver. The spleen cyto sols from vitamin E and selenium deficient rats had approximately 5 fo ld higher activity than the samples from animals maintained on diets s ufficient in these two nutrients (control) or deficient in either nutr ient alone. The calcium-dependent PLA(2) activity was about 6 fold hig her in spleen cytosol of vitamin E and selenium deficient rats compare d with cytosolic samples from animals on the other three diets. Time c ourse studies indicated that in rats the calcium-independent phospholi pase A(2) activity in lung, fiver, and spleen increased initially betw een 4 and 6 weeks of consuming the diets deficient in both vitamin E a nd selenium, mid increased even further again at 7 weeks. This bi-phas ic response to the deficiency occurred I week after indicators of vita min E and Se status had reached minimum levels. When animals that were maintained oil the deficient diet for 6 weeks consumed the control di rt for I week the phospholipase A(2) activity of lung, liver, mid sple en was not different than the activity of the control animals. The mal ondialdehyde concentration of lung and spleen measured at 6 and 7 week s correlated positively with the calcium-independent phospholipase A(2 ) activity. These results indicate that deficiency of vitamin E and se lenium in the rat leads to a bi-phasic increase in calcium-independent PLA(2) activity in rat lung, liver and spleen, and that the initial i ncrease can be reversed by partial repletion of the two antioxidant nu trients.