Effects of short-term administration of conjugated linoleic acid on lipid metabolism in white and brown adipose tissues of starved/refed Otsuka Long-Evans Tokushima Fatty rats

The present study explored the short-term effects of dietary conjugated linoleic acid (CLA) on body fat accumulation and lipid metabolism in starved/refed Otsuka Long-Evans Tokushima Fatty (OLETF) rats. Male OLETF rats of 12-weeks-old were starved for 24 h and then re-fed for 48 h either with CLA diet [7.5% CLA and 7.5% safflower oil (SAF)] or SAF control diet (15% SAF oil). The results demonstrated a 27% reduction of white adipose tissue wet weight (total of epididymal and perirenal adipose tissue weight) in the CLA group compared to the control group. The activity of mitochondrial carnitine palmitoyltransferase (CPT), the rate-limiting enzyme for fatty acid oxidation, was significantly elevated by 1.7- and 1.6-fold in perirenal white adipose tissue and interscapular brown adipose tissues, respectively, in the CLA group compared to the control. In contrast, phosphatidate phosphohydrolase (PAP), the rate-limiting enzyme for triglyceride (TG) synthesis, was found to be 23 and 15% lower, in perirenal white- and brown- adipose tissue of CLA-fed rats, respectively. In addition, CLA feeding led to a significant reduced concentration of serum total- and HDL-cholesterol and phospholipid, Thus, dietary CLA evidently lowers abdominal white adipose tissue wet weight through an enhanced fatty acid oxidation and a reduced TG synthesis.