Cytokines [interleukin (IL-1, chemokines/intercrines, interferon, tumor necrosis factor-alpha (TNF-alpha)] induce anorexia when administered intracerebroventricularly (i.c.v.) at estimated pathophysiological concentrations. Here, the effects of the i.c.v. microinfusion (1.0, 20 and 100 ng) of activators of glycoprotein (gp) 130, a common signal transducer among receptors for members of the IL-6 subfamily [IL-6, IL-11, ciliary neurotrophic factor, leukemia inhibitory factor (LIF), oncostatin M (OSM)], on short-term feeding in rats were investigated. Several members of the IL-6 subfamily induced anorexia, IL-11 was the most potent, LIF the most effective, and OSM had no effect. The results suggest that IL-6 subfamily members act centrally to decrease feeding and this effect may participate in the anorexia which frequently accompanies pathological processes. This action could interact with the anorexigenic effect of other cytokines released during disease.