Genes involved in amino acid metabolism are differentially regulated by saturated and polyunsaturated dietary fat

Abstract

Previous studies have shown that Wy 14643, a synthetic PPAR‐alpha ligand, down‐regulates the expression of the histidine degrading enzyme, histidase (HAL) gene. In addition fatty acids are natural ligands of PPAR‐alpha with higher affinity for polyunsaturated fatty acids (PUFAs). Therefore, the aim of the present work was to study the effect of a diet rich in PUFAs (soybean oil) or saturated (coconut oil) dietary fat on the expression of genes involved in amino acid metabolism such as HAL, tyrosine aminotransferase (TAT), serine dehydratase (SDH), and the sodium‐dependant neutral amino acid transporter (SNAT2). We also measured the gene expression of PPAR‐alpha, and its coactivator PGC1. Our results showed that the gene expression of HAL, TAT, SDH and SNAT2 increased between 100–200% when the rats were fed with saturated fat when compared with rats fed with corn oil (control group). The gene expression of these genes showed a 20% to 50% decrease in the liver of the rats fed with soybean oil when compared with the control group. PPAR‐alpha and PGC‐1 gene expression decreased by approximately 30% in the rats fed with coconut oil, and about 60% in those fed with soybean oil, when compared with the rats fed with corn oil. Our results suggest that amino acid catabolism may be regulated by the kind of dietary fat via PPAR‐alpha.