RELATIONSHIP OF BODY ENERGY STATUS TO INFLAMMATION-INDUCED ANOREXIA AND WEIGHT-LOSS

The response to acute inflammation of rats at two levels of prior weig ht reduction were compared with normal-weight rats to examine how prio r alterations in body energy status influence inflammation-induced ano rexia and weight loss. Specifically, body weights were either reduced by 6%, the level of weight loss expected in normal-weight rats followi ng induction of acute inflammation, or by 12%, a level 6% below that e xpected of the normal-weight rats. Rats were either allowed to eat ad lib. on postinflammation Day 1 or were kept on food restriction until Day 5, when anorexia was no longer expected to be present. As predicte d, normal-weight rats allowed to eat ad lib. beginning Day 1 displayed the most severe anorexia. Total food intake of this group over the fi rst 5 days following inflammation induction was 33% less than the cont rol (CON) group. Rats with 6% prior weight reduction displayed a milde r anorexia, eating only 15% less than the CON group over the first 5 d ays. In contrast, rats with 12% prior weight reduction ate the same am ount of food as the CON group. Interestingly, similar feeding patterns were observed in rats that resumed ad lib. feeding on Day 5. The outc ome of these various feeding patterns was to bring body weights of all the inflammation groups to the same level, approximately 6% below CON group weights. These results provide further evidence that proinflamm atory mediators induce a temporary reduction in the amount of body tis sue (weight) spontaneously maintained that is directly proportionate t o the magnitude of insult. (C) 1998 Elsevier Science Inc.