Body energy status and the metabolic response to acute inflammation.

An animal model of acute inflammation was used to examine how body energy status influences the syndrome of anorexia, negative nitrogen balance, and body weight loss typically seen in response to injury. Specifically, the metabolic response to acute inflammation was studied in rats of normal, elevated, or reduced body weights. Rats induced to overeat and gain weight prior to inflammation displayed protracted anorexia, greater subsequent weight loss, higher metabolic rates, and greater negative energy balance than rats of normal weight. Conversely, rats with reduced body weights displayed elevated food intakes, body weight gain, attenuated nitrogen loss, and normal rates of energy expenditure. Prior weight reduction did not affect postinflammation fever or levels of fibrinogen, iron, and interleukin-6-like activity, suggesting that the ability to mount an acute phase response was not impaired in weight-reduced rats. These results suggest that the usual postinflammation adjustments in body energy flux and body nitrogen are regulated components of a metabolic response to acute inflammation which renders normally protected sources of endogenous energy and substrate available for repair and recovery.