EFFECTS OF LENTINAN ON ABNORMAL INGESTIVE BEHAVIORS INDUCED BY TUMOR-NECROSIS-FACTOR

Lentinan (LNT), a beta-glucan derived from Lentinus edodes (Berk.) Sig n., is known to work positively against cachexia in patients with mali gnant tumors. Because the cachectin/tumor necrosis factor (TNF) is sup posed to be one of the factors that mediate cancer cachexia, we tested the effects of LNT on TNF-induced cachexia in rats. First, we analyze d in detail the cachectic actions of TNF (0.2 mg/kg/day, 5 days, IV) o n food and water intake, body weight, and locomotor activity. The day after the first administration of TNF (acute phase), food and water in take, as well as body weight, of all rats decreased. However, over the next few days of treatment (chronic phase), the rats gradually develo ped a tolerance to the cachectic actions of TNF. Specifically, after t he third administration, the rats treated with TNF had a higher amount of water intake than the control rats. This was mainly due to an incr ease in daytime water intake. We also analyzed the effects of LNT (0.1 or 1.0 mg/kg, twice/wk, IV) on TNF-induced cachexia, and compared the data with those from the rats treated with TNF alone. The higher dosa ge of LNT significantly suppressed TNF-induced daytime polydipsia and increased the amount of nighttime wafer intake, as well as the meal si ze of nighttime food intake. These results suggest that LNT partially normalizes TNF-induced cachexia in rats. (C) 1997 Elsevier Science Inc .