LOSS OF RED-BLOOD-CELL GLUTATHIONE DURING MG DEFICIENCY - PREVENTION BY VITAMIN-E, D-PROPRANOLOL, AND CHLOROQUINE

Mg deficiency results in loss of red blood cell glutathione and was th ought to be due to decreased Mg-dependent synthesis. The effects of vi tamin E, D-propranolol, and chloroquine on red blood cell glutathione levels in Mg-deficient rats were examined. Feeding the rats a Mg-defic ient diet for 3 wk resulted in an similar to 80% decrease in serum Mg and a 55% loss of red blood cell glutathione; concomitantly, plasma th iobarbituric acid reactive (TEAR) materials rose 240%, All three drug treatments had no effect on the plasma Mg levels but significantly inh ibited the rise in TEAR content and attenuated (60-80% effective) the loss of glutathione. Red blood cell ghost membranes from the Mg-defici ent rats also exhibited 2.3-fold higher TEAR content, which was attenu ated by vitamin E treatment. With isolated red blood cells from Mg-suf ficient rats, loss of glutathione could be induced by a chemical oxyra dical system. Direct protective effects were afforded by cw-tocopherol and D-propranolol but not by chloroquine. The data suggest that 1) th e loss of glutathione during Mg deficiency was due to increased oxidat ive degradation, 2) both vitamin E and D-propranolol protected by a me mbrane antiperoxidative action, and 3) chloroquine probably protected by diminishing prooxidant activity secondary to its inhibition of cyto kine induction during Mg deficiency.