Meal related effects of IV glucose, glucagon and insulin on blood glucose level: Role in glucoregulation exhibited by self-injecting rats

Abstract

In previous works, it was demonstrated that rats self-injected with (IV) glucose, insulin and/or glucagon and that the self-administration pattern was related to the meal. It was suggested that the different preprandial or postprandial blood glucose level (B.G.L) determinated the meal and were dependent on it. Previously self-injected amounts of glucose, glucagon and insulin were here injected by an automatic device and their effect on B.G.L. were compared in the post and preprandial conditions. Results indicated that the effects of insulin, glucagon and glucose on B.G.L., which were different during the postprandial hyperglycemia compared to the preprandial normoglycemia, accounted for the different self-injection patterns. Furthermore successive injection of glucose and insulin or glucagon and insulin suggest that rats, by pressing alternatively two levers performed a regulatory correction of variations of their B.G.L. It is concluded that rats may learn to perform a behavioral regulation of their B.G.L. by IV self-injections of glucose and glucoregulatory hormones.