Kinetics and thermogenesis of medium-chain monocarboxylic and dicarboxylic acids in man: sebacate and medium-chain triglycerides

The effects on oxygen consumption and carbon dioxide production of a constant intravenous infusion of 0.15 g of disodium sebacate (Sb), the sodic salt of a medium-chain dicarboxylic acid with 10 carbon atoms, per kilogram of body weight per hour over 5 hours and a 50% mixture of medium- and long-chain triglycerides (MCT/LCT) were compared in 10 healthy men. Oxygen consumption and carbon dioxide production were measured by indirect calorimetry. Mean oxygen consumption was about 19% higher than the basal oxygen consumption at the end of MCT/LCT infusion but was only 5% higher than the basal oxygen consumption when Sb was infused. There was an eightfold increase in plasma beta-hydroxybutyrate and acetoacetate concentrations and a threefold increase in serum insulin levels during MCT/LCT infusion, but no significant change in ketone bodies and insulin from basal values was observed during and after Sb infusion. Pharmacokinetic parameters were also computed, showing an average apparent volume of distribution of 167 mL/kg of body weight for MCTs and 112 mL/kg of body weight for Sb. The t1/2 of MCTs was 50 minutes and that of Sb was 78 minutes. Urinary excretion of Sb and its beta-oxidative by-product, suberic acid, globally accounted for 48% of the given amount of Sb. In spite of its urinary loss and slower tissue uptake compared with MCTs, Sb avoided ketone body formation or elevation in insulin levels and did not induce a significant increase in oxygen consumption.(ABSTRACT TRUNCATED AT 250 WORDS)