Bombesin produces hypothermia in insulin treated rats

Previous studies have shown that central injection of bombesin produces hypothermia in food-deprived, but not food satiated rats at normal ambient temperatures. The present study evaluated the effects of bombesin on core body temperature (Tb) and feeding behavior in rats pretreated with insulin. Administration of bombesin (0.25, 0.5, and 1.0 microgram) into the lateral cerebral ventricle produced hypothermia in rats injected with insulin (10 U/kg; i.m.). No significant change in core temperature was observed in control rats following bombesin. Insulin treatments significantly stimulated feeding behavior and the highest dose of bombesin significantly reduced feeding behavior. The results demonstrate bombesin-induced hypothermia under metabolic conditions similar to acute starvation. These findings are consistent with the hypothesis that bombesin-induced hypothermia in food-deprived rats is directly related to the fasting state.