Importance of the intestine as a site of metformin‐stimulated glucose utilization

Abstract

1 The intestine has been implicated as a site of increased glucose utilization by the antihyperglycaemic drug, metformin. This study makes a quantitative assessment of this effect. 2 Glucose utilization by the intestine and hind limb region was determined by arterial-venous glucose difference adjusted for blood flow rate in fasted rats receiving a hyperglycaemic hyperinsulinaemic infusion. 3 Intrajejunal administration of metformin, 250 mg kg⁻¹, increased glucose disposal during the infusion procedure, associated with increased glucose utilization in the intestine by 69% and in the hind limb region by 40%. 4 Metformin, 250 mg kg⁻¹, increased glucose disappearance during an intravenous glucose tolerance test. This was accompanied by increased uptake of tritiated 2-deoxy-d-glucose into the intestinal mucosa to a greater extent than into skeletal muscles (per unit wet weight of tissue). 5 The results demonstrate that the intestinal mucosa is a quantitatively important site of increased glucose utilization during the blood glucose-lowering effect of metformin.