Isatin inhibits food intake in mice

Isatin (2,3-dioxindole) is an endogenous compound which is distributed throughout the central nervous system. The studies reported here demonstrate that isatin decreased food intake in food deprived TAC (SW) male mice 12-16 weeks of age. Isatin was more effective at decreasing food intake when the mice had to work harder to obtain food. Isatin also decreased sucrose, milk and water intake. When hunger was reduced by prefeeding milk to the mice, isatin was more effective at decreasing food intake. Isatin did not alter spontaneous activity in an openfield. Behaviors observed in the home cage indicated that mice which received isatin approached the food more often without eating than the controls. Movement in the home cage was significantly reduced in mice receiving isatin. Drinking, grooming and resting were not significantly affected by administration of isatin. These studies suggest that isatin may be an endogenous modulator of food intake.