A metabolomic investigation of splanchnic metabolism using 1H NMR spectroscopy of bovine blood plasma

This is the first study introducing an NMR-based metabolomic approach to elucidate metabolism in the portal-drained viscera and liver. High-resolution H-1 NMR spectroscopy was performed on blood plasma obtained from the mesenteric artery, the hepatic portal vein and the hepatic vein of steers before and after interruminal infusion of short-chain fatty acids (SCFA). Partial least squares regression discriminant analysis (PLS-DA) on H-1 NMR spectra obtained for arterial and portal plasma samples revealed increases in the intensities of spectral regions that could mostly be assigned to the methyl group of propionate, P-hydroxybutyrate as well as acetate in portal plasma samples compared with arterial plasma samples. PLS-DA on portal and hepatic plasma samples showed decreases in the intensities of spectral regions corresponding to the regions where methyl and methylene groups of n-butyrate, propionate, iso-butyrate, valerate, iso-valerate as well as lactate are reported to have chemical shifts. In addition, spectral differences likely to reflect a hepatic excretion of P-hydroxybutyrate and glucose were observed between portal and hepatic samples. All findings were supported by traditional biochemical analyses. Consequently, the present study clearly demonstrated the great potential of the NMR-based metabolornic approach for elucidating splanchnic metabolism. In addition, prediction of metabolite concentrations from the H-1 NMR spectra obtained on plasma samples was investigated using PLS, which in relation to use I H NMR spectra quantitatively revealed promising results with R-values in the region of 0.87-0.98. (c) 2004 Elsevier B.V All rights reserved.