Whole blood and plasma amino acid transfers across the portal drained viscera and liver of the pig

Whole blood (WB) and plasma (P) amino acid transfers across the portal drai ned viscera and the liver were determined during 6 h of a constant p-aminoh ippuric acid infusion in three hourly-fed Landrace x Large-White pigs (30.5 kg, mean live weight) surgically prepared with chronically inserted cathet ers in a mesenteric vein (MV), the portal vein (PV), an hepatic vein (HV) a nd the carotid artery (CA). Plasma and WE amino acid concentrations were de termined in the CA, PV and HV. The plasma/WB ratios showed no significant d ifferences for vessels except for lysine and glutamate for which this ratio is significantly higher in the HV and in the PV for lysine. This suggests that the PV lysine and HV glutamate were preferentially transported in the plasma. In the PV, threonine, valine and alanine are transported by both pl asma and red blood cells. These data show that the contribution of plasma a nd whole blood to amino acid transport can be different between amino acids and between individual tissues. (C) Inra/Elsevier, Paris.