Sensitivity of liver cells formed after partial hepatectomy to glucagon, vasopressin and angiotensin II

Abstract

During the active proliferation which follows partial hepatectomy, the sensitivity of liver cells to glucagon is markedly diminished. In hepatocytes obtained from rats partially hepatectomized 3 days before experiments were performed, the dose-response curves to glucagon were shifted to the right by about two orders of magnitude as compared to those of the control cells. Later on (7 days after surgery) the dose-response to glucagon was still shifted to the right but by only one order of magnitude. These data are consistent with the diminution in the number of glucagon receptors in liver plasma membrane during liver regeneration reported by other authors. No stimulation of glycogenolysis, gluconeogenesis or ureogenesis was produced by vasopressin or angiotensin II in hepatocytes from rats partially hepatectomized 3 days before experimentation. However, phosphatidylinositol labeling was stimulated in these cells to a similar extent as in the controls. The ionophore A23187 was also ineffective in stimulating glycogenolysis in these cells. Later, 7 days after surgery, the hepatic responsiveness to vasopressin and angiotensin II was restored. The data suggest that, during the initial stages of liver regeneration, the enzymatic machinery of the hepatocyte is not sensitive to calcium-signalling.