title: Fish oil and the pan-PPAR agonist tetradecylthioacetic acid affect the amino acid and carnitine metabolism in rats.
abstract: Peroxisome proliferator-activated receptors (PPARs) are important in the regulation of lipid and glucose metabolism. Recent studies have shown that PPARα-activation by WY 14,643 regulates the metabolism of amino acids. We investigated the effect of PPAR activation on plasma amino acid levels using two PPARα activators with different ligand binding properties, tetradecylthioacetic acid (TTA) and fish oil, where the pan-PPAR agonist TTA is a more potent ligand than omega-3 polyunsaturated fatty acids. In addition, plasma L-carnitine esters were investigated to reflect cellular fatty acid catabolism. Male Wistar rats (Rattus norvegicus) were fed a high-fat (25% w/w) diet including TTA (0.375%, w/w), fish oil (10%, w/w) or a combination of both. The rats were fed for 50 weeks, and although TTA and fish oil had hypotriglyceridemic effects in these animals, only TTA lowered the body weight gain compared to high fat control animals. Distinct dietary effects of fish oil and TTA were observed on plasma amino acid composition. Administration of TTA led to increased plasma levels of the majority of amino acids, except arginine and lysine, which were reduced. Fish oil however, increased plasma levels of only a few amino acids, and the combination showed an intermediate or TTA-dominated effect. On the other hand, TTA and fish oil additively reduced plasma levels of the L-carnitine precursor γ-butyrobetaine, as well as the carnitine esters acetylcarnitine, propionylcarnitine, valeryl/isovalerylcarnitine, and octanoylcarnitine. These data suggest that while both fish oil and TTA affect lipid metabolism, strong PPARα activation is required to obtain effects on amino acid plasma levels. TTA and fish oil may influence amino acid metabolism through different metabolic mechanisms.
authors.affiliation: Department of Clinical Science, University of Bergen, Bergen, Norway. Bodil.Bjorndal@k2.uib.no
authors.forename: Bodil
authors.initials: B
authors.lastname: Bjørndal
authors.forename: Trond
authors.initials: T
authors.lastname: Brattelid
authors.forename: Elin
authors.initials: E
authors.lastname: Strand
authors.forename: Natalya Filipchuk
authors.initials: NF
authors.lastname: Vigerust
authors.forename: Gard Frodahl Tveitevåg
authors.initials: GF
authors.lastname: Svingen
authors.forename: Asbjørn
authors.initials: A
authors.lastname: Svardal
authors.forename: Ottar
authors.initials: O
authors.lastname: Nygård
authors.forename: Rolf Kristian
authors.initials: RK
authors.lastname: Berge
mesh_terms: D000596:Amino Acids / Q000097:blood / Q000378:metabolism*; D064751:Ammonium Compounds / Q000097:blood; D000818:Animals; D001835:Body Weight / Q000187:drug effects; D002331:Carnitine / Q000031:analogs & derivatives* / Q000096:biosynthesis / Q000097:blood / Q000378:metabolism*; D004032:Diet; D005247:Feeding Behavior / Q000187:drug effects; D005395:Fish Oils / Q000494:pharmacology*; D005786:Gene Expression Regulation / Q000187:drug effects; D008099:Liver / Q000187:drug effects / Q000378:metabolism; D008297:Male; D047492:Peroxisome Proliferator-Activated Receptors / Q000819:agonists* / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D013440:Sulfides / Q000494:pharmacology*; D014508:Urea / Q000097:blood
chemical_list: D000596:Amino Acids; D064751:Ammonium Compounds; D005395:Fish Oils; D047492:Peroxisome Proliferator-Activated Receptors; D013440:Sulfides; C116917:acylcarnitine; C062078:1-(carboxymethylthio)tetradecane; D014508:Urea; D002331:Carnitine