Effects of parenteral arginine supplementation on the intestinal adaptive response after massive small bowel resection in the rat

Background. Arginine (ARG;) and its metabolic products (polyamines and nitr ic oxide) are known to affect gut function and protein synthesis in various tissues. The aim was to study the effect of parenteral ARG supplementation on intestinal adaptation and intestinal function in rats after massive sma ll bowel resection (SBR). Methods. Fasted rats (275 g) were studied 24 h after 80% SBR. At t = 6 h, t = 12 h, and t = 18 h after SBR, a 300 mM ARG solution (ARG, n = 9), 5 ml/1 00 g body weight, was given subcutaneously. Controls received iso-osmolaric amounts of NaCl (NaCl, n = 9) or alanine (ALA, n = 8). Twenty-four hours a fter operation substrate fluxes across the gut were determined together wit h intestinal protein synthesis, polyamine concentrations in gut tissue, and gut function by testing intestinal permeability using the urinary recovery of lactulose and rhamnose. Results. Intestinal fluxes did not differ among groups, except for an incre ased production of ornithine and a decreased uptake of glutamine after ARG; supplementation. Also, intracellular arginine and ornithine concentrations were higher in the jejunum, accompanied by lower concentrations of other a mino acids. Intracellular putrescine and gamma-aminobutyric acid, a breakdo wn product of putrescine, were higher. However, spermidine and spermine wer e not. Protein synthesis was lower in the ARC: group, while intestinal perm eability decreased. Conclusions. Parenteral arginine supplementation in rats with massive SBR l eads to a slowing of intestinal adaptation, indicated by reduced glutamine uptake and protein synthesis. The exact mechanism of this inhibitory effect remains to be elucidated. Intestinal permeability, however, benefits from arginine supplementation, possibly related to better enterocyte differentia tion. (C) 1999 Academic Press.