Determination of plasma lipid hydroperoxides by an NADPH/NADP+ coupled enzyme reaction system. Evaluation of a method.

Several techniques based on different principles have been proposed to measure lipid hydroperoxides. Enzymatic methods are sensitive and can be quite specific but they are subject to interference by inhibitors and not all are stoichiometric. The present work proposes some modifications of the Heath & Tappel (Anal Biochem 1976; 7:184-91) enzymatic method of determination of lipid hydroperoxides in order to standardize and automate it and to meet the analytical criteria required for a biological assay. The proposed new protocol and the automated assay give acceptable within-run and between-run precisions, with coefficients of variation of 3.34% and 5.80%, respectively, at the usual plasma lipid hydroperoxides content. The recovery is 98.7 +/- 4.89%, and the method is linear for a wide range of contents and sensitive (10 mumol/l) enough to measure the plasma lipid hydroperoxides content.