TEMPORAL CHANGES IN MEAL NUMBER AND MEAL SIZE RELATIONSHIP IN RESPONSE TO RHU IL-1-ALPHA

PERIPHERALLY infused interleukin-l reduces food intake. Its temporal a nd selective effects on meal number and meal size were investigated in seven rats continuously infused for 3 days with recombinant human int erleukin-1 alpha (rHu IL-1 alpha; 3 mu g day(-1), i.v.). Food intake d ecreased significantly during the first two infusion days, and was bro ught about by first the early reduction of meal number, followed by me al size with a 1 day delay. The primary effect of rHu IL-1 alpha: was seen during the dark cycle, After the infusion was stopped, meal numbe r recovered most quickly, followed by a lag in recovery of meal size. We conclude that rHu IL-1 alpha influenced food intake primarily via a n effect on meal number, which responds more rapidly than a decrease i n meal size, thereby inducing an immediate decrease in food intake.