CHEMOKINES/INTERCRINES AND CENTRAL REGULATION OF FEEDING

Chemokines/intercrines are structurally and functionally related cytokines that induce specific actions on the immune system and are released in response to infection, inflammation, and trauma. These pathological processes are frequently accompanied with food intake suppression. In the present study, the action of chemokines/intercrines on the regulation of feeding was investigated using the intracerebroventricular microinfusion of chemokine/intercrine-alpha subfamily members [interleukin-8 (IL-8); growth-related cytokine/melanoma growth-stimulating activity (GRO-alpha/MGSA); platelet factor-4 (PF-4); beta-thromboglobulin (beta-TG); and interferon-inducible protein-10 (IP-10)] and beta-subfamily members [monocyte chemotactic protein-1/monocyte chemotactic and activating factor (MCP-1/MCAF); regulated upon activation normal T-cell expressed and presumably secreted (RANTES); macrophage inflammatory protein-1 alpha (MIP-1 alpha); and macrophage inflammatory protein-1 beta (MIP-1 beta)]. The doses administered were 1.0, 20, and 100 ng/rat of the chemokine/intercrine. The intracerebroventricular administration of three members of the alpha-subfamily (IL-8, PF-4, and IP-10) and two members of the beta-subfamily (MCP-1/MCAF and RANTES) decreased the short-term (2-h) food intake. These effective chemokines/intercrines, however, were significantly less potent than IL-1 beta in decreasing feeding. The results support the hypothesis that only a subset of immunomodulators released during pathological processes may participate in the regulation of feeding with different potencies.