HYPERGLYCEMIC EFFECT OF INSULIN

Abstract

Various pancreatic substances, including most insulin prepns., induce an immediate hyperglycemia when injd. intraven. This phenomenon is of interest in view of evidence suggesting that the pancreas may produce a substance which opposes the action of insulin. The initial hyperglycemia which characterizes insulin prepns. persists after its hypoglycemic activity is destroyed by reduction-inactivation. Expts. were done to investigate the hyperglycemic effects of crystalline and amorphous insulin prepns., to determine their influence on blood ketone levels and to decide whether the hyperglycemic material could neutralize the action of insulin. The crystalline and amorphous prepns. subjected to cysteine inactivation produced very similar hyperglycemic effects in normal dogs. In pancreatectomized dogs, the hyperglycemic effects were slight and the blood acetone-body levels tended to rise during the hyperglycemic phase. The inactivated material showed no ability to protect mice from insulin-induced convulsions. It is concluded that the basis for the action of this hyperglycemic material on blood sugar and ketone levels is its ability to release hepatic glycogen stores. The question whether or not this factor has a normal function as an internal secretion of the pancreas remains to be answered.