Secretion and Significance of the Incretin Hormones on the Postprandial Glycemic Response in Type-1 Diabetes Mellitus

GLP-1 and GIP are incretin hormones secreted from specific endocrine celles in the gut. Stimulus for secretion is prescence of carbohydrates, fat and protein in the gut. The incretin hormones controls postprandial glucose excursions through stimulation of insulinsecretion as well as inhibition of glucagon and gastric emptying.The effects of GLP-1 on insulin secretion and glucagon inhibition are glucose dependent and the risc of hypoglycemia is therefore negligible when the hormone is administered in supra physiological concentrations.Furthermore, some animal studies suggest that GLP-1 has a trofic effect on the betacells and the hormone has been shown to replenish intracellular stores of insulin. Because the main bloodglucose lowering effect of GLP-1 has been thought to be due to increased insulin secretion, analouges of the hormone has been developed for the treatment of type-2 diabetes. So far, relatively little is known about the effect of GLP-1 in type-1 diabetes.It possible, that GLP-1 in combination with insulin (possibly mainly through its effect on glucagon inhibition and gastric emptying) could reduce the need for exogenous insulin with a concomitant reduced risc of hypoglycemia. Without compromising the target glucemic control. This study focuses of the postprandial bloodglucose lowering effects of endogenous as well as exogenous GLP-1 in patients with type-1 diabetes according to residual betacell function and glycemic control.Furthermore, the endogenous secretion of incretin hormones in patients with type-1 diabetes mellitus will be compared to that of matched normal controls.