INTERLEUKIN-1 RECEPTOR ANTAGONIST BLOCKS EFFECTS OF IL-1-ALPHA AND IL-1-BETA ON SOCIAL-BEHAVIOR AND BODY-WEIGHT IN MICE

To compare the effects of interleukin-la (IL-1-alpha) and interleukin-1-beta (IL-1-beta) on behaviour and body weight, mice were injected ip with various doses of these cytokines (human recombinant forms) and their interest toward a juvenile conspecific as well as their body weight were measured at different intervals after treatment. IL-1-beta was about 10 times more active than IL-1-alpha to decrease social investigation and induce weight loss, but the time course of these effects was the same for both cytokines. Pretreatment with a 1,000 fold excess of a specific antagonist of IL-1 receptors (IL-1ra) blocked the effects of IL-1-alpha and IL-1-beta, demonstrating the specificity of action of these cytokines.