Luminescence in the study of lipid metabolism

Using bioluminescence assays for glycerol, free fatty acids, beta-hydroxybutyrate and lactate, we were able to perform complex studies of human energy and lipid metabolism both in serum samples in vivo and in isolated fat cells in vitro. These studies would have been impossible without reliable, specific and highly sensitive luminescence methods. Oxidatively modified low density lipoprotein (LDL) has been implicated in the pathogenesis of atherosclerosis. Adaptation of a chemiluminescence assay for lipid hydroperoxides to LDL isolated by specific precipitation from serum makes it possible to measure LDL oxidation in vivo. Cell dependent chemiluminescence was used to investigate whether receptor mediated endocytosis of LDL by macrophages leads to oxygen radical production in these cells. No activation of the membrane NAD(P)H oxidase was observed.