Effects of dietary arginine supplementation on protein turnover and tissueprotein synthesis in scald-burn rats

We assessed the effects of dietary arginine supplementation on protein turn over and organ protein synthesis in burned rats. Male Wistar rats weighing about 200 g underwent catheter jejunostomy and received scald bums covering 30% of the whole-body surface area. Animals were divided into a control gr oup (n = 9) and an arginine group (n = 9) and continuously received total e nteral nutrition for 7 d (250 kcal . kg(-1) d(-1), 1.72 gN kg(-1) d(-1)). C hanges in body weight, plasma total protein, plasma albumin, urinary excret ion of polyamines, nitrogen balance, whole-body protein kinetics, and tissu e protein synthesis rates were determined. Whole-body protein kinetics and tissue fractional protein synthetic rates (Ks, percent/d) were estimated us ing a 24-h constant enteral infusion of N-15 glycine on the last day. The c hanges in body weight were not different between the control and arginine g roups. The urinary excretion of polyamines was higher in the arginine group than in the control group (P < 0.01). Burned rats enterally fed arginine-s upplemented diet yielded significantly greater cumulative and daily nitroge n balance on days 3 and 5 than those fed a control diet (cumulative, P < 0. 05; day 3, P < 0.01; day 5, P < 0.01). Whole-body protein turnover rate was significantly elevated in the arginine group as compared to that in the co ntrol group (P < 0.05). The Ks of rectus abdominis muscles were significant ly increased in the arginine group in comparison to the control group (P < 0.01). We have shown that dietary arginine supplementation improved protein anabolism and attenuated muscle protein catabolism after thermal injury. ( C) Elsevier Science Inc.