1H NMR metabolomic and transcriptomic analyses reveal urinary metabolites as biomarker candidates in response to protein undernutrition in adult rats

1H NMR metabolomics was performed on urine samples weekly and on plasma and liver samples collected at week 4 from these animals, to identify metabolites that respond to protein undernutrition. To further investigate metabolites which were fluctuated in response to protein undernutrition in terms of metabolic enzymes, hepatic mRNA microarray and quantitative PCR analyses were also performed at week 4. Adult male Wistar rats were fed an 14% casein, control (CT) diet or an isocaloric [5% casein, low protein (LP)] diet for 4 weeks. 1H nuclear magnetic resonance metabolomic analysis was performed on urine samples weekly and on plasma and liver samples at week 4 to identify metabolites that respond to protein undernutrition. Liver samples were also subjected to mRNA microarray and quantitative PCR analyses at week 4 to further investigate metabolites responsive to protein undernutrition in terms of metabolic enzymes.