Different proliferative responses of periportal and perivenous hepatocytes to EGF.

Stimulation of DNA synthesis by EGF was compared in cultured periportal and perivenous hepatocyte populations. Periportal hepatocytes responded to EGF more sensitive (IC50-values 20 vs 75 ng/ml) and with a higher maximal stimulation (420 vs 290%) than perivenous hepatocytes with respect to both [3H]thymidine incorporation and labeling index. The glutamine synthetase-positive hepatocytes responded much less to EGF than did the perivenous cells in general. The simultaneous presence of insulin increased the sensitivity for EGF predominantly in the periportal hepatocytes. These inherent differences in the growth potential of hepatocytes from different acinar localizations may contribute to different growth patterns across the lobules in normal and regenerating liver.