Parenteral multivitamin supplementation induces both oxidant and antioxidant responses in the liver of newborn guinea pigs

Background: The multivitamin solution is a major component of photo-induced generation of peroxides in parenteral nutrition. The aim of this study was to determine whether the parenteral multivitamin preparation induces in the liver a peroxide-induced oxidant challenge or an antioxidant protection associated with the antiradical components of the solution. Methods: Newborn guinea pigs were infused with dextrose supplemented with peroxides (250 mu mol/L H2O2 or 350 mu mol/L tert-butylhydroperoxide) or with a multivitamin preparation (MVP, 18 vol/vol). after 3 days, total glutathione and a free radical-sensitive eicosanoid marker (prostaglandin I-2 [PGI(2)]/total prostaglandins) were measured in livers. Results: There was a significant decrease in the PGI(2)/total prostaglandin ratio (mean +/- SEM) [dextrose: 0.068 +/- 0.007 vs. (dextrose +/- H2O2: 0.048 +/- 0.001, dextrose + TBH: 0.043 +/- 0.001)] and glutathione concentrations decreased [dextrose: 55 +/- 7 vs. (dextrose + H2O2: 37 +/- 7, dextrose + TBH: 18 +/- 7 nmol/mg protein)] after infusion of peroxides. Despite the peroxide load in the multivitamin solution, it did not alter the measured variables as prostanoid ratio remained at control concentrations (dextrose: 0.066 +/- 0.008 vs. dextrose + MVP: 0.065 +/- 0.006), as did glutathione levels (dextrose: 52 +/- 6 vs. dextrose + MVP: 45 +/- 7 nmol/mg prot). Conclusion: In the liver of guinea pig pups, infused peroxides cause oxidation of membrane-derived prostanoids. The decrease in glutathione in response to administration of peroxides suggests consumption rather than a response to a free radical attack. Despite the oxidant load associated with peroxides generated in MVP, the multivitamin preparation protected membranes as the prostanoid ratio, and glutathione levels remained at control levels.