Islet transplantation into rat liver: in vitro secretion of insulin from the isolated perfused liver and in vivo glucagon suppression.

Islet isografts were injected into the portal veins of rats made diabetic with streptozotocin. The isografts normalized not only plasma glucose and insulin levels but also the elevated plasma immunoreactive glucagon level. The in vitro basal insulin secretion and prompt sensitivity to glucose were shown directly by perfusing isolated livers containing transplanted islets. In vitro glucagon secretion to an arginine stimulus could not be demonstrated, although it would have been expected demonstrated, although it would have been expected in normal islets. Thus, it appears that insulin derived from transplanted islets is capable of correcting endogenous hyperglucagonemia and of ameliorating the effects of experimental diabetes while transplanted islet glucagon secretion is relatively suppressed.