Enteral alanyl-glutamine supplement promotes intestinal adaptation in rats

Although parental administration of glutamine promotes intestinal adaptation, it is controversial whether enteral glutamine is effective after small bowel resection. To further evaluate the benefits of enteral supplementation, peptide and amino acid peptide transporter function must be considered. We evaluated the effect of enteral alanyl-glutamine based on the alteration of peptide and amino acid transporter expressions after massive small intestinal resection. Rats underwent 80% proximal intestinal resection. Expression of the glutaminase (GA), amino acid transporter B0 and peptide transporter PepT1 mRNA in the residual intestinal cells was initially examined by Northern blot analysis. Rats with a small bowel received a bolus supplement of glutamine (2.0 g/kg/day) + alanine (1.22 g/kg/day) mixture, alanyl-glutamine (2.972/kg/day) or saline for 3 days from one day before operation. On the 3rd postoperative day (POD) and the 7th POD, residual intestinal tissue was removed, and mucosal parameters were measured. The GA activity and GA mRNA significantly increased on the 1st POD. Although the levels of B0 mRNA gradually decreased, the PepT1 mRNA increased after surgery, and reached 150% of the initial level on the 5th POD. In the rats administered alanyl-glutamine, mucosal wet weight and protein content similarly increased with increasing villus height on the 7th POD. Enteral supplementation with alanyl-glutamine but not glutamine + alanine mixture promotes intestinal adaptation as evidenced by increased peptide transport after intestinal resection.