MULTIPLE CYTOKINES AND ACUTE-INFLAMMATION RAISE MOUSE LEPTIN LEVELS -POTENTIAL ROLE IN INFLAMMATORY ANOREXIA

Several inflammatory cytokines, most notably tumor necrosis factor (TN F) and IL-1, induce anorexia and loss of lean body mass, common manife stations of acute and chronic inflammatory conditions. In C57BL/6 fema le mice, the administration of TNF, IL-1, and, to a lesser extent, leu kemia inhibitory factor (LIF), produced a prompt and dose-dependent in crease ill serum leptin levels and leptin mRNA expression in fat. IL-1 0, IL-4, ciliary neurotrophic factor, and IL-2, cytokines not known to induce anorexia or decrease food intake, had no effect on leptin gene expression or serum leptin levels. After administration of Escherichi a coli lipopolysaccharide (LPS), leptin gene expression and leptin lev els were increased. These findings suggest that leptin levels may be o ne mechanism by which anorexia is induced during acute inflammatory co nditions.