Effect of insulin on potassium and glucose movement in perfused rat liver

Abstract

When the liver from a normal rat is transferred to an extracorporeal perfusion apparatus, there is a marked release of potassium and glucose to the perfusing medium attributed primarily to the anoxia incident to removal of the liver from the intact animal. This glycogenolytic response subsided within 30 min as reflected by a rapid uptake of glucose in the absence of a recovery of potassium when livers were perfused with whole blood and a decreased outflow of glucose when livers were perfused with diluted blood. The administration of insulin during this recovery phase resulted in a prompt uptake of potassium from whole-blood perfusate which preceded any demonstrable increase in the uptake of glucose by the liver. These findings indicate that the extracorporeal perfused rat liver is responsive to added insulin despite the initial anoxia and suggest 1) that insulin is required by the liver for the recovery of potassium lost during glycogenolysis and 2) the transfer of glucose into the liver is dissociated from the transfer of K+. In perfusions with diluted blood, insulin inhibited the net accumulation of perfusate glucose, an effect possibly accounted for by a net decrease in the breakdown of liver glycogen.