RESUMO
BACKGROUND/AIMS: The presence of receptors for epidermal growth factor (EGF) on beta cells in the rat pancreatic islets has been established, but the physiological role remains to be settled. The aim of the present study was to evaluate the effect of EGF on glucose homeostasis. METHODS: Fasted rats were treated with intraperitoneal injections of 10, 40 or 80 microg/kg body weight, either with EGF or 1% bovine serum albumin (controls). In a second experiment, fasted rats received an intraperitoneal injection of 1 mg glucose/kg body weight, followed by an injection of EGF or bovine serum albumin. Blood was drawn before the injections and at different time points afterwards. The plasma concentrations of glucose, insulin and glucagon were measured. RESULTS: A modest elevation of the concentrations of glucose and insulin in plasma during the study was found in fasted rats in experiment 1. The increase in insulin concentration was attenuated by EGF, but after glucose injection this effect was reversed. Plasma glucagon levels were dose-dependently elevated by EGF and increased instead of decreased after glucose injection. CONCLUSION: Our data suggest that EGF might play an important role in the regulation of glucagon secretion by preventing the lowering effect of glucose on plasma glucagon levels.