In vitro oxidation of essential amino acids by jejunal mucosal cells of growing pigs
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This study was conducted to test the hypothesis that porcine jejunal mucosal cells can degrade all essential amino acids (EAA). Jejunal mucosal cells (primarily enterocytes) were isolated from 50-day-old healthy pigs and incubated at 37 °C for 45 min in Krebs buffer containing plasma concentrations of amino acids and one of the following l-[1-14C]- or l-[U-14C]-amino acids plus unlabeled tracers at 0.5, 2, or 5 mM: histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine. There was active transamination of leucine, isoleucine and valine in the cells (1.35-2.5 nmol/mg protein per 45 min at 2 mM), with most (67-71%) of their α-ketoacids released into the medium. In contrast, catabolism of methionine and phenylalanine was negligible (0.04-0.05 nmol/mg protein per 45 min at 2 mM) and that of other EAA was completely absent in these cells. These results indicate that intestinal mucosal cells are a site for the substantial degradation of branched-chain amino acids but not other EAA in pigs. © 2007 Elsevier B.V. All rights reserved.
author list (cited authors)
Chen, L., Yin, Y., Jobgen, W. S., Jobgen, S. C., Knabe, D. A., Hu, W., & Wu, G.