BACKGROUND: Amino acid glutamine plays a central role in inter-organ nitrogen transfer in acidosis, a compensatory mechanism that is essential in maintaining acidbase balance. Intestinal glutamine absorption is a key exogenous glutamine source in maintaining glutamine homeostasis. The purpose of this in vivo study was to investigate the regulation of intestinal glutamine absorption during chronic metabolic acidosis. METHODS: Metabolic acidosis in adult male Sprague-Dawley rats was induced by adding 1.5% NH4Cl to drinking water. [3H]-L-glutamine transport activity across brush border membrane vesicles and glutamine transporter ATB0 messenger RNA levels by relative reverse transcriptase-polymerase chain reaction were measured in rat jejunum. Data were analyzed by t test (P < .05). RESULTS: Acidosis occurred as early as 1 day and was partially compensated by 7 days. Glutamine transport in brush border membrane vesicles was increased after 2 days of acidosis. Chronic acidosis (7 days) resulted in an 8-fold increase of glutamine transport activity. The glutamine transport maximal capacity (Vmax) was stimulated 5-fold, while the transport affinity (Km) was not affected by acidosis. Relative reverse transcriptase-polymerase chain reaction showed a 2.5-fold increase of glutamine transporter ATB0 messenger RNA levels. CONCLUSIONS: Chronic metabolic acidosis stimulates intestinal glutamine absorption via a mechanism that involves an increase of functional membrane glutamine transporter units. Copyright 2004 Elsevier Inc.
BACKGROUND:Amino acid glutamine plays a central role in inter-organ nitrogen transfer in acidosis, a compensatory mechanism that is essential in maintaining acidbase balance. Intestinal glutamine absorption is a key exogenous glutamine source in maintaining glutamine homeostasis. The purpose of this in vivo study was to investigate the regulation of intestinal glutamine absorption during chronic metabolic acidosis. METHODS:Metabolic acidosis in adult male Sprague-Dawley rats was induced by adding 1.5% NH4Cl to drinking water. [3H]-L-glutamine transport activity across brush border membrane vesicles and glutamine transporter ATB0 messenger RNA levels by relative reverse transcriptase-polymerase chain reaction were measured in rat jejunum. Data were analyzed by t test (P < .05). RESULTS:Acidosis occurred as early as 1 day and was partially compensated by 7 days. Glutamine transport in brush border membrane vesicles was increased after 2 days of acidosis. Chronic acidosis (7 days) resulted in an 8-fold increase of glutamine transport activity. The glutamine transport maximal capacity (Vmax) was stimulated 5-fold, while the transport affinity (Km) was not affected by acidosis. Relative reverse transcriptase-polymerase chain reaction showed a 2.5-fold increase of glutamine transporter ATB0 messenger RNA levels. CONCLUSIONS:Chronic metabolic acidosis stimulates intestinal glutamine absorption via a mechanism that involves an increase of functional membrane glutamine transporter units. Copyright 2004 Elsevier Inc.
Authors: M P K J Engelen; C L N De Castro; E P A Rutten; E F M Wouters; A M W J Schols; N E P Deutz Journal: Clin Nutr Date: 2012-06-06 Impact factor: 7.324