LIPID MOBILIZATION IN RELATION TO BODY COMPOSITION IN MAN

The concentrations in plasma of free fatty acids, glycerol and immunoreactive insulin and the turnover rates of free fatty acids and glycerol were measured by constant infusion of albumin complexed palmatic-1-14C and glycerol-2-3H and correlated with body fat and body fat/body cell mass, obtained by isotope dilution determinations of total water and total exchangeable potassium, in a material of patients with a wide variation in body composition and without diabetes mellitus. Free fatty acid concentration and turnover rate correlated strongly as well as glycerol concentration and turnover rate. Free fatty acid turnover rate/glycerol turnover rate was above three, but not different at different body composition. Free fatty acid concentration showed a trend to positive correlation with body fat and body fat/body cell mass, while glycerol concentration showed a significant positive correlation with these parameters. Insulin was positively correlated with body fat and showed a trend to correlation with body fat/body cell mass. These results indicate that with increasing body fat, or obesity, lipid mobilization and lipolysis are increasing. No correlation between body cell mass and lipid mobilization or lipolysis was found. It therefore appears likely that some factor in adipose tissue is responsible for the increased lipid mobilization and lipolysis in obesity. © 1969.