Islet transplantation with a bioartificial pancreas is a potential alternative to whole pancreas transplantation. The authors constructed a bioartificial pancreas using mesh reinforced polyvinyl alcohol hydrogel tubes (MRPT), in an attempt to clarify the in vitro responsiveness to glucose of islets seeded in the MRPT. When the MRPT were perfused in a small chamber with buffer containing 3.3 mmol or 16.7 mmol glucose, insulin release from the MRPT began to increase at 9 +/- 3 min, reaching a plateau at approximately 40 min after the glucose concentration in the perfusate increased from 3.3 to 16.7 mmol. When MRPT seeded with islets were subjected to static incubation in buffer containing 3.3 mmol or 16.7 mmol glucose, insulin release from the MRPT remained elevated for 3 hr of high glucose stimulation, the amount of secreted insulin depending upon the number of islets seeded. Although pre incubation of semipermeable membranes in culture medium containing fetal bovine serum prior to seeding with islets has recently been reported to improve insulin release, the authors found that such pre treatment of the MRPT did not have a beneficial effect. Their in vitro findings in this study suggest that the bioartificial pancreas using MRPT could be a promising therapeutic approach to human diabetes mellitus.