Metabolic consequences of dietary medium-chain triglycerides in the rat
Wiley, J.H.; Leveille, G.A.
Journal of Nutrition 103(6): 829-835
1973
ISSN/ISBN: 0022-3166 PMID: 4705268 Document Number: 62410
Some metabolic effects of feeding rats on medium-chain triglyceride (MCT), triglyceride containing primarily C8 and C10 fatty acids, were compared with the effects of triglycerides composed of long-chain fatty acids. Rates of lipogenesis in vitro in liver and adipose tissue of rats receiving long-chain triglycerides were significantly depressed relative to rates in tissues of rats on a low-fat diet. MCT was much less effective in depressing lipogenesis. Malic enzyme, citrate cleavage enzyme and glucose-6-phosphate dehydrogenase together with 6-phosphogluconate dehydrogenase enzyme activities were depressed in rat liver by adding triglycerides containing long- or medium-chain fatty acids to a low-fat diet. In adipose tissue MCT was much less effective than triglycerides containing long-chain fatty acids in depressing the activity of these enzymes. Circulating amounts of beta -hydroxybutyrate were raised by MCT feeding. Adding maize oil or MCT to the low-fat diet appeared to increase circulating insulin, whereas only maize oil increased circulating triglycerides. The lack of effect of MCT on lipogenesis is attributed to its portal absorption and rapid uptake and oxidation by the liver. Results support the theory that long-chain fatty acids or their CoA derivatives are involved in regulation of fat synthesis in both liver and adipose tissue.