Inhibitors of prostaglandin synthesis do not improve food intake or body weight of tumor-bearing rats.

Interleukin-1 (IL-1) and tumor necrosis factor (TNF) are immunoregulatory cytokines that mediate many aspects of the acute phase response to infection and injury. It has been hypothesized that these cytokines mediate the onset of the cachexia-anorexia syndrome with tumor growth. The anorexigenic effects of IL-1 are mediated in part by prostaglandins (PG). Therefore, the purpose of the present study was to determine if administration of ibuprofen (ibu) or indomethacin (indo), which inhibit PG synthesis, would affect the food intake and body weight of tumor-bearing rats. Rats were implanted with the Morris 7777 hepatoma, a tumor known to induce anorexia and weight loss in rats, and weight loss and leukocyte synthesis of IL-1 and TNF in mice. Treatment with indo or ibu did not improve food intake or body weight in the tumor-bearing rats. However, administration of ibu coincident with tumor implantation did result in smaller tumor mass compared to placebo-treated controls. The results of the present study suggest that PG synthesis is not a major factor in the onset of anorexia in this animal model of tumor-induced anorexia. However, further studies of the effects of inhibitors of PG synthesis on the kinetics of tumor growth are clearly indicated. Copyright 1999 John Wiley & Sons, Inc.