Lack of relationship between blood glucose-lowering activity of colestimide and serum cholecystokinin (CCK) concentrations in patients with type 2 diabetes.

Colestimide has been reported to lower blood glucose levels in patients with type 2 diabetes and hypercholesterolemia. We investigated the mechanism of the hypoglycemic activity of colestimide by examining changes in serum cholecystokinin (CCK) and insulin concentrations before and after its 2-week oral administration. A total of seven type 2 diabetes inpatients with hypercholesterolemia received colestimide after their blood glucose levels had stabilized. We daily measured plasma glucose levels and serum lipid concentrations, calculated Body Mass Index (BMI), and determined whole-day changes in serum immunoreactive insulin (IRI) and CCK concentrations in all study subjects. We daily measured plasma glucose levels, as well as serum IRI and CCK concentrations at 10 time points for measurement. Plasma glucose levels, as well as serum IRI and CCK concentrations before and after the 2-week oral administration of colestimide were compared. The means of total cholesterol levels and BMI decreased significantly after administration. At time points for measurement (10 : 00 and 12 : 00), plasma glucose levels decreased significantly after administration (P=0.026 and P=0.009, respectively). Diurnal changes in serum IRI and CCK concentrations were not observed after administration, except for the IRI concentration at 20: 00. The effect of colestimide on CCK may not explain the mechanism of its blood glucose-lowering activity in patients with type 2 diabetes and hypercholesterolemia.