Dietary lipids regulate b-oxidation enzyme gene expression in the developing rat kidney

Ouali, F., F. Djouadi, C. Merlet-Bénichou, and J. Bastin. Dietary lipids regulate b-oxidation enzyme gene expression in the developing rat kidney. Am. J. Physiol. 275 (Renal Physiol. 44): F777–F784, 1998.—This study examines the ability of dietary lipids to regulate gene expression of mitochondrial and peroxisomal fatty acid b-oxidation enzymes in the kidney cortex and medulla of 3-wk-old rats and evaluates the role of glucagon or of the a-isoform of peroxisome proliferator-activated receptor (PPARa) in mediating b-oxidation enzyme gene regulation in the immature kidney. The long-chain (LCAD) and medium-chain acyl-CoA dehydrogenases (MCAD) and acyl-CoA oxidase (ACO) mRNA levels were found coordinately upregulated in renal cortex, but not in medulla, of pups weaned on a high-fat diet from day 16 to 21. Further results establish that switching pups from a lowto a high-fat diet for only 1 day was sufficient to induce large increases in cortical LCAD, MCAD, and ACO mRNA levels, and gavage experiments show that this upregulation of b-oxidation gene expression is initiated within 6 h following lipid ingestion. Treatment of pups with clofibrate, a PPARa agonist, demonstrated that PPARa can mediate regulation of cortical b-oxidation enzyme gene expression, whereas glucagon was found ineffective. Thus dietary lipids physiologically regulate gene expression of mitochondrial and peroxisomal b-oxidation enzymes in the renal cortex of suckling pups, and this might involve PPARa-mediated mechanisms.