pH is decreased in transplanted rat pancreatic islets

Recent studies of transplanted pancreatic islets have indicated incomplete revascularization. We investigated the pH, in relation to oxygen tension (Po-2), in endogenous, islets and islets syngeneically transplanted to the renal subcapsular site of nondiabetic and streptozotocin-diabetic recipients. Tissue pH and Po-2 were measured using microelectrodes. In the endogenous islets, tissue pH was. similar. to that in arterial blood. In the transplanted islets tissue, pH was 0.11-0.15 pH units lower.. No differences in islet graft pH were seen between nondiabetic and diabetic animals, and none if the islet grafts were investigated 1 day or 1 mo posttransplantation. The Po-2 in the endogenous islets was similar to35 mmHg. Transplanted islets had a markedly lower tissue Po-2 both 1 day and 1 mo after transplantation. A negative correlation between the tissue Po-2 and the.. hydrogen ion concentration was seen in the 1-mo-old islet transplants in diabetic animals. In conclusion, decreased Po-2 in transplanted islets is associated with a decreased tissue pH suggesting a shift toward more anaerobic glucose metabolism after transplantation.