Splanchnic, renal, and muscle clearance of alanylglutamine in man and organ fluxes of alanine and glutamine when infused in free and peptide forms

H Lochs, E Roth, S Gasic, W Hübl, EL Morse, SA Adibi - Metabolism, 1990 - Elsevier
H Lochs, E Roth, S Gasic, W Hübl, EL Morse, SA Adibi
Metabolism, 1990Elsevier
The present study was designed to investigate organ metabolism of intravenously (IV)
infused (100 μmol· h− 1· kg− 1) alanylglutamine and its amino acid constituents in a group of
healthy subjects. The dipeptide clearance (μmol/min) by kidney (51±3) was significantly (P<.
01) greater than the clearance by either splanchnic organs (19±6) or skeletal muscle (21±8).
Infusion of alanylglutamine significantly (P<. 01) increased arterial plasma concentrations of
free alanine (260±31 v 330±38 μmol/L) and free glutamine (620±66 v 764±65 μmol/L) when …
Abstract
The present study was designed to investigate organ metabolism of intravenously (IV) infused (100 μmol · h−1 · kg−1) alanylglutamine and its amino acid constituents in a group of healthy subjects. The dipeptide clearance (μmol/min) by kidney (51 ± 3) was significantly (P < .01) greater than the clearance by either splanchnic organs (19 ± 6) or skeletal muscle (21 ± 8). Infusion of alanylglutamine significantly (P < .01) increased arterial plasma concentrations of free alanine (260 ± 31 v 330 ± 38 μmol/L) and free glutamine (620 ± 66 v 764 ± 65 μmol/L) when compared with the baseline period. Concurrently, splanchnic uptake of alanine and glutamine increased and muscle release of alanine ceased. However, muscle release of glutamine remained unaffected. Renal balances of alanine and glutamine changed from neutral to negative (net release) and from positive (net uptake) to neutral, respectively. Infusion of a corresponding mixture of alanine and glutamine had similar effects on arterial plasma concentrations and splanchnic and muscle balances of alanine and glutamine, but had no effect on renal balances of these amino acids. From these studies in man, we conclude that kidney predominates over other organs in clearance of alanylglutamine from plasma and that this may account for the different effect of infusion of alanine and glutamine in free and peptide forms on renal fluxes of these amino acids.
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