Nitrogen retention in rats fed on diets enriched with arginine and glycine

Abstract

1. Adult rats were subjected to a brief period of diethyl ether anaesthesia and were given diets with 200 or 100 g casein/kg with or without arginine plus glycine supplementation in the post-anaesthesia period. Nitrogen retention was measured as well as liver protein content and liver and muscle transaminase activities (l-aspartate aminotransferase (GOT), (EC 2.6.1.1), and l-alanine aminotransferase (GPT) (EC 2.6.1.2)).2. Results demonstrated that anaesthesia-stressed rats consuming the high-protein diet with supplemental arginine and glycine retained twice as much N as did rats given the diet with 200 g casein/kg alone, for the first 5 d post-anaesthesia.3. Anaesthesia-stressed animals consuming the diets with 100 g casein/kg with or without arginine plus glycine supplementation did not differ from each other in N retention.4. Liver protein content increased after anaesthesia in rats given the high-protein diets; liver transaminase activity increased, whereas muscle transaminase activity decreased, in animals consuming the high protein diets.5. Possible mechanisms to account for these results are discussed.