[Effect of glucose and of insulin on the fast induced decrease of insulin response to glucose of the in vitro...

A 24 hours fast decreases by 50% the first and second phases of insulin response to glucose by the isolated and perfused rat pancreas, while the response to tolbutamide remains unchanged. Intra peritoneal administration of low doses of glucose (0.3 g), four times during fasting restored the insulin response. Administration of insulin (0.25 U x 4). Tolbutamide (1.25 mg x 4) or L-leucine (0.1 g x 4), did not. These results show that an exogenous or endogenous insulin impregnation is not the factor responsible for the maintenance of the B cell gluco-receptor during fasting.