Demonstration of a d-glucose transport system in the biliary tree of the rat by use of the segmented retrograde intrabiliary injection technique

Using the segmented retrograde intrabiliary injection (SRII) technique, a 40-μl segment of radioactive d-glucose solution was washed into the biliary tree with 100 μl saline. The total volume exceeded the distended biliary tree capacity of the rat; nevertheless, about 18 per cent of the administered dose of glucose was retained by the membranes of the biliary tree and was recovered in recollected bile. Changes in this retained fraction were used to demonstrate the presence of a glucose transport system in the hepatobiliary system of the rat. The intraportal administration of phlorizin enhanced the biliary retention of [¹⁴C]-D-glucose and [¹⁴C]methyl-α-D-glucopyranoside given by SRII. Phlorizin treatment had no effect on the biliary retention of [³H]mannitol, [³H]-3-O-methyl glucose or [³H]sucrose. The i.v. administration of a large loading dose of d-glucose also produced an increase in the hepatobiliary retention of [¹⁴C]-d-glucose given by SRII. Furthermore, if d-glucose or methyl-α-d-glucopyranoside was added to the SRII solution of [¹⁴C]-d-glucose, the retention of labeled glucose was enhanced. Mannitol and 3-O-methyl glucose had no such effect. Therefore, the experimental results demonstrated that. in the biliary tree of the rat, there existed a system which shows high selectivity for transferring d-glucose from bile to liver.