Regulation of Appetite and Gastrointestinal Microflora: Role of a Fecal Anorexigenic Substance (FS-.T)

A fecal anorexigenic substance (FS-T) was isolated from feces of conventional rats and mice. Effect of FS-T on food intake was compared between conventional (CV) and germfree (GF) animal. FS-T induced significant feeding suppression in CV and GF mice by intraperitoneal injection, but no difference was found between CV and GF in the degree of the effect. Oral administration of FS-T did not induce anorexia in either CV or GF mice, and spontaneous food intake was not different between CV and GF mice. These data showed that the bacterial products such as FS-T in gastrointestinal tract did not cause anorexia in CV animal, though FS-T was an anorexigenic factor when it was injected intraperitoneally.