Modification of liver cell volume by insulin and glucagon.

Cell volume plays a decisive role in the regulation of hepatic metabolism. The present study has been performed to test for an effect of insulin and glucagon on liver cell volume. To this end, the effect of these hormones has been studied in isolated perfused rat livers and isolated rat hepatocytes. Insulin leads to rapid stimulation of cellular K+ uptake and increase of cell volume, effects reversed by glucagon or cAMP. The insulin stimulated cellular K+ uptake is significantly decreased in the presence of either loop diuretics (furosemide or bumetanide) or amiloride and is completely inhibited in the presence of both, bumetanide and amiloride. The glucagon stimulated cellular K+ release in the presence of insulin is blunted by K+ channel blocker quinidine. The effects of insulin and glucagon on liver cell volume could participate in the regulation of hepatic metabolism by these hormones.