EPIDERMAL GROWTH-FACTOR INDUCES CELL-PROLIFERATION IN MOUSE PANCREAS AND SALIVARY-GLANDS

Epidermal growth factor (EGF) is a mitogenic stimulus in many tissues and occurs in large amounts in the pancreas and salivary glands. Wheth er EGF is mitogenic in the pancreas is controversial, and the EGF effe ct has not been studied in the salivary glands. Therefore, the aim of the present study was to investigate the possible effects on the pancr eas and parotid and submandibular glands at different time intervals a fter exogenous EGF administration Human recombinant EGF was infused su bcutaneously by osmotic minipumps in three groups of mice (for 1, 3, a nd 7 days, respectively) at a dosoge of 10 mu g/kg/h (1.6 mu mol/kg/h) . Tritiated thymidine was infused intraperitoneally by osmotic minipum ps for the same time periods. but only for the last 3 days in the 7-da y group. After 1 day the pancreas increased in weight and the increase persisted throughout the study. No effect was seen on the parotid or submandibular gland wet weight. A slight transient increase in pancrea s protein content was observed, whereas amylase content was unaffected . The labeling index of serous and ductal cells in the parotid gland i ncreased from the third day. After 7 days, all cell types studied in t he pancreas and parotid and submandibular glands were in a hyperprolif erative state. The results show that EGF evoked a strong proliferative response on all cell types studied in the pancreas and parotid and su bmandibular glands.