ETHANOL DECREASES THE LEVELS OF GLUT2 GLUCOSE-TRANSPORTER MESSENGER-RNA IN HEPATOCYTES

In order to elucidate the implication of GLUT2 in the impaired glucose metabolism caused by ethanol, we examined if ethanol affects GLUT2 gl ucose transporter mRNA expression in the liver After the adult rats we re fed with and/or without ethanol for 1 or 4 weeks, hepatocytes were isolated and total RNA was extracted from them. The levels of GLUT2 mR NA in hepatocytes isolated from 1 week-ethanol fed rats estimated by N orthern blot analysis did not change compared to those of untreated ra ts, those levels in hepatocytes from 4 weeks-ethanol fed rats decrease d markedly. Studies were also performed using primary rat hepatocyte c ultures in vitro. We found that ethanol, when added to cultured hepato cytes, resulted in a substantial reduction in the levels of GLUT2 mRNA and this effect was only observed after 24 hr exposure of ethanol. Th us, ethanol seems to have a direct inhibitory effect on GLUT2mRNA in t he liver, which may eventually cause the impaired glucose tolerance.