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 nitric 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 small 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/100 g body weight, was given subcutaneously. Controls received iso-osmolaric amounts of NaCl (NaCl, n = 9) or alanine (ALA, n = 8). Twenty-four hours after operation substrate fluxes across the gut were determined together with 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 increased 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 amino acids. Intracellular putrescine and gamma-aminobutyric acid, a breakdown product of putrescine, were higher. However, spermidine and spermine were not. Protein synthesis was lower in the ARG group, while intestinal permeability decreased.
CONCLUSIONS: Parenteral arginine supplementation in rats with massive SBR leads 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 differentiation. Copyright 1999 Academic Press.