Effects of conjugated linoleic acid on serum leptin concentration, body-fat accumulation, and beta-oxidation of fatty acid in OLETF rats

We investigated the efficacy of a 4-wk supplementation of conjugated linole ic acid (CLA) as free fatty acid (FFA) or triacylglycerol (TG) on serum lep tin concentration, body-fat accumulation, and mitochondrial P-oxidation in Otsuka Long-Evans Tokushima Fatty (OLETF) rats. A significant reduction of serum leptin concentration (42%) and a decrease in the wet weights of perir enal, epididymal, and omental/ visceral-adipose tissue in TG-CLA and FFA-CL A groups were found in comparison with the OLETF control group. Both forms of CLA supplementation produced a 5.2% decrease in body weight compared wit h the control even though food intake was similar in the OLETF groups. More over, both forms of CLA enhanced carnitine-palmitoyltransferase activity in brown adipose tissue, perirenal adipose tissue, red gastrocnemius muscle, and liver in comparison with the OLETF control group. Serum concentrations of non-esterified fatty acid and TG also were reduced in rats fed diets sup plemented with TG-CLA and FFA-CLA.