Comparative Effects of Epidermal Growth-Factor, An Insulin-Glucagon Combination, and a Hepatocyte Growth-Factor Preparation On Epidermal Growth-Factor Receptors

We investigated the changes in cell surface epidermal growth factor (EGF) receptors in the liver after partial hepatectomy, and in primary adult rat hepatocyte cultures following stimulation with either EGF, or a preparation of hepatocyte growth factor, or an insulin-glucagon combination. We confirmed a reduction in EGF receptors on hepatocytes after partial hepatectomy and a rapid down-regulation of EGF receptors on normal hepatocytes in vitro following exposure to EGF. Insulin and glucagon and hepatocyte growth factor, whilst initiating hepatocyte DNA synthesis, had only slight effects on their EGF binding capacity and EGF-receptor affinity. These results indicate that changes in cell membranes early in proliferation have only non-specific effects on EGF receptors, and, therefore, support the role of ligand binding to the EGF receptor as an important component of hepatocyte proliferation in vivo