Ex Vivo Method to Simultaneously Evaluate Glucose Utilization, Uptake, and Production in Rat Liver

A novel ex vivo method to simultaneously evaluate hepatic glucose utilization, uptake, and production was developed in rats. The right lateral lobe of the liver was perfused with Krebs-Henseleit bicarbonate buffer containing 5 mmol/L uniformly labeled ¹³C-glucose ([U-¹³C]-glucose). The whole glucose concentration in the perfusate was measured by colorimetric assay, and the concentrations of [U-¹²C]-glucose (natural isotope) or [U-¹³C]-glucose were estimated on the basis of the abundance ratio of [U-¹²C]-glucose or [U-¹³C]-glucose, which were measured by GC-MS. The difference in whole glucose and [U-¹³C]-glucose concentrations between the baseline and effluent perfusate represents hepatic glucose utilization and glucose uptake, respectively. The [U-¹²C]-glucose concentration in the effluent perfusate corresponds to hepatic glucose production. With this method, we clarified the precise mechanism that underlies the hepatic impairment of diabetic animals and pharmacological effects of anti-diabetic agents. Thus, this method is useful for the pathophysiological and pharmacological research of type 2 diabetes.