The effect of gliclazide (a hypoglycemic sulphonylurea; 200 micrograms/ml) on the absorption and utilization of glucose and lactate production was investigated by using an in vitro perfused intestine-pancreas preparation isolated from fed rats, after intraluminal or arterial glucose administration. In the absence of intraluminal glucose administration, both glucose utilization and lactate production seem to be dependent on the arterial glucose concentration. The glucose utilization by the intestine was significantly increased in the presence of gliclazide (200 micrograms/ml) at three arterial concentrations of glucose (2.75, 5.5 and 11.0 mmol/l) without increasing the lactate production. The translocation of glucose from the lumen to the blood after intraluminal sugar administration was reduced when the glucose concentration was increased in the perfusate. In the presence of gliclazide (200 micrograms/ml) the translocation of glucose from the lumen to the blood was significantly reduced at the three arterial concentrations of glucose without affecting the intestinal absorption rate. In conclusion, gliclazide 200 micrograms/ml, increases the metabolic utilization of both arterially or intraluminally supplied glucose in isolated and perfused rat intestine-pancreas.