Possible role of intestinal fatty acid oxidation in the eating-inhibitory effect of the PPAR-α agonist Wy-14643 in high-fat diet fed rats

• Published in: PloS one Vol. 8; no. 9; p. e74869
• Main Authors: Karimian Azari, Elnaz, Leitner, Claudia, Jaggi, Thomas, Langhans, Wolfgang, Mansouri, Abdelhak
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 17.09.2013; Public Library of Science (PLoS)
• Subjects: 3-Hydroxybutyric Acid - blood; Activation; Animals; Carnitine; Carnitine O-Palmitoyltransferase - genetics; Carnitine O-Palmitoyltransferase - metabolism; Carnitine palmitoyltransferase; Coenzyme A; Conditioning; Diabetes; Diet; Diet, High-Fat; Duodenum; Energy; Energy Metabolism - drug effects; Enzymes; Esterification; Fatty acids; Fatty Acids - metabolism; Feeding Behavior - drug effects; Food; Food intake; Gene expression; Gene Expression Regulation - drug effects; High fat diet; Hydroxymethylglutaryl-CoA Synthase - genetics; Hydroxymethylglutaryl-CoA Synthase - metabolism; Insulin; Intestine; Intestines - metabolism; Jejunum; Jejunum - drug effects; Jejunum - metabolism; Ketogenesis; Laboratories; Latency; Lipid metabolism; Lipid Metabolism - drug effects; Lipids; Liver; Male; Metabolism; Mitochondria; Obesity; Oxidation; Oxidation-Reduction; Palmitoyltransferase; Peroxisome proliferator-activated receptors; Pharmacology; Physiology; Portal vein; PPAR alpha - agonists; Proteins; Pyrimidines - administration & dosage; Pyrimidines - pharmacology; Rats; Respiratory quotient; Rodents; United States > US; Switzerland
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0074869

PPAR-α plays a key role in lipid metabolism; it enhances fatty acid oxidation (FAO) and ketogenesis. Pharmacological PPAR-α activation improves insulin sensitivity and reduces food intake, but its mechanisms of action remain unknown. We here report that intraperitoneal (IP) administration of the PPAR-α agonist Wy-14643 (40 mg/kg BW) reduced food intake in adult male rats fed a high-fat diet (HFD, 49% of the energy) mainly through an increase in the latency to eat after injection, and without inducing a conditioned taste avoidance. Also, IP administered Wy-14643 caused an acute (the first 60 min) decrease in the respiratory quotient (RQ) and an increase in hepatic portal vein β-hydroxybutyrate level (at 35 min) without affecting plasma non-esterified fatty acids. Given the known stimulatory effect of PPAR-α on FAO and ketogenesis, we measured the protein expression level of carnitine palmitoyltransferase-1 (CPT 1A) and mitochondrial 3-hydroxy-3-methylglutaryl-coenzyme A synthase (HMG-CoAS2), two key enzymes for FAO and ketogenesis, respectively, in liver, duodenum and jejunum. Wy-14643 induced a significant increase in the expression of CPT 1A in the jejunum and duodenum and of HMG-CoAS2 in the jejunum, but neither CPT 1A nor HMG-CoAS2 expression was increased in the liver. The induction of CPT 1A and HMG-CoAS2 expression was associated with a decrease in the lipid droplet content selectively in the jejunum. Our findings indicate that Wy-14643 stimulates FAO and ketogenesis in the intestine, in particular in the jejunum, rather than in the liver, thus supporting the hypothesis that PPAR-α activation inhibits eating by stimulating intestinal FAO.