Epidermal growth factor receptor number decreases during rat liver regeneration

The potential role of epidermal growth factor (EGF) in the regulation of rat liver regeneration was examined by assessing the binding of 125I-EGF to hepatic membranes isolated at various times after partial hepatectomy. The results demonstrated a fall in 125I-EGF binding detectable as early as 8 h after partial hepatectomy. The nadir in EGF binding, less than 40% of that observed in sham-operated control rats, was seen 36 and 48 h after partial hepatectomy. Scatchard analysis showed that the decrease in binding capacity was due to a fall in receptor number. The specificity of the observed loss of EGF receptors was substantiated in parallel studies of 125I-insulin and 125I-wheat germ lectin binding; the binding of these ligands did not decrease appreciably during liver regeneration. The data are consistent with the hypothesis that EGF or a similar substance is one component of the complex humoral signal that regulates liver regeneration.