The incorporation of glucose and palmitic acid into lipids in human arterial intima and media in vitro

Abstract

Summary The incorporation into lipids of [ 14 C]glucose and [ 14 C]palmitate with and without unlabelled glucose in defined samples of apparently normal, fresh human intima and media was measured in vitro . After incubation of the intima samples with [ 14 C]-glucose about 50 % and 15 % of the label occurred in triglycerides and lecithin, respectively. A moderate degree of activity was found in phosphatidyl inositol and cholesterol and/or diglyceride; in other lipid classes the activity was low with the exception of a varying degree of label in free fatty acids. After incubation with [ 14 C]palmitate the distribution of label was similar but the proportion of label in triglycerides and lecithin was reversed and the degree of labelling of sphingomyelin was higher. After addition of unlabelled glucose the above differences for the [ 14 C]-glucose and [ 14 C]palmitate precursors were partially levelled out. The differences were less pronounced for the media samples. The rates of incorporation of the respective precursors were similar in intima and media both on a dry weight and DNA basis. The distribution of label in triglycerides and lecithin after incubation with [ 14 C]palmitate agrees well with results obtained by others for species susceptible to experimentally induced or spontaneous atherosclerosis but deviates from more atherosclerosis-resistant species. It is possible that this correlation reflects important factors for the formation of atherosclerosis.