Polyunsaturated fatty acid profiles and alpha-tocopherol levels in plasma and whole blood incubated with copper. Evidence of inhibition of lipoperoxidation in plasma by hemolysate.

Polyunsaturated fatty acid (PUFA) profiles and alpha-tocopherol levels were studied in human plasma and whole blood incubated with copper under air or nitrogen. In plasma, both PUFAs and alpha-tocopherol disappeared. The results were completely different in whole blood: (i) in plasma, while alpha-tocopherol decreased in the same manner as in plasma incubated alone, profiles of PUFA were only slightly modified. So, in spite of the absence of alpha-tocopherol, lipoperoxidation was not very marked. That is why the release of a protective factor from erythrocytes during hemolysis was under consideration. This was confirmed by the complete inhibition of degradation of PUFAs in plasma when hemolysate was added; (ii) In erythrocytes, no modification in PUFA profiles could be detected while alpha-tocopherol decreased slightly. Thus, not only do erythrocytes resist the copper-dependent oxidative stress in an incredible manner, but they also seem to protect plasma at the time of hemolysis.