EFFECT OF ACUTE ETHANOL TREATMENT ON EPIDERMAL GROWTH-FACTOR RECEPTORIN THE RAT STOMACH

The present study investigated the effect of acute ethanol (ETOH) trea tment on the epidermal growth factor (EGF) receptor in rat gastric muc osa using two different experimental models. In the in vitro experimen ts, gastric mucosal cells were incubated with 0, 0.05, 0.1, 0.25, and 0.5% ethanol in Dulbecco's modified Eagle's medium (DMEM) for 30 min a nd then used for the membrane preparation. The EGF receptor binding as say indicated that cells incubated in the presence of ethanol displaye d a concentration-dependent increase (r = 0.85) in the I-125-EGF bindi ng. The Western blot analysis using anti-EGF-receptor antibody reveale d that ethanol in vitro caused reduction in the immunoreactivity of th e major 170-kDa protein. There were also alterations in the minor prot ein bands(140, 120, and 50 kDa). In the in vivo experiments, rats that fasted overnight were given 1.0 mi of saline or ethanol (5, 10, or 15 %) by gastric intubation 30 min before sacrifice. In comparison with t he saline controls, ethanol treatment caused a decrease of the EGF rec eptor binding to the gastric mucosal membrane (saline: 5%:10%:15% ETOH , 1.46 +/- 0.18:1.13 +/- 0.17:1.27 +/- 0.19:0.84 +/- 0.14, p < 0.02; m ean a SEM, n = 9). Furthermore, the immunoblot analysis revealed conce ntration-dependent decrease in the intensity of the major 170-kDa prot ein with ethanol. The reduction in the EGF receptor binding and the im pairment of the receptor protein might be due to the nonspecific damag e of the gastric mucosal membrane by ethanol.