Increased intracellular localization of brain GLUT-1 transporter in response to ethanol during chick embryogenesis.
Fetal exposure to ethanol is associated with growth retardation of the developing central nervous system. We have previously described a chick model to study the molecular mechanism of ethanol effects on glucose metabolism in ovo. Total membrane fractions were prepared from day 4, day 5, and day 7 chick embryos exposed in ovo to ethanol or to vehicle. By Western blotting analysis, ethanol exposure caused a mean 7- to 10-fold increase in total GLUT-1 and a 2-fold increase in total GLUT-3. However, glucose uptake by ethanol-treated cells increased by only 10%. Analysis of isolated plasma (PM) and intracellular (IM) membranes from day 5 cranial tissue revealed a mean 25% decrease in GLUT-1 in the PM and a 66% increase in the IM in the ethanol group vs. control. The amount of PM GLUT-3 was unchanged but that of IM GLUT-3 was significantly decreased. The data suggest that GLUT-3 cell surface expression may be resistant to the suppressive effects of ethanol in the developing brain of ethanol-treated embryos. The overall increase in GLUT-1 may reflect a deregulation of the transporter induced by ethanol exposure. The increased IM localization and decreased amount of PM GLUT-1 may be a mechanism used by the ethanol-treated cell to maintain normal glucose uptake despite the overall increased level of the transporter.
Carver
F M
FM
Department of Biochemistry, School of Medicine, East Carolina University, Greenville, North Carolina 27858, USA. carver@brody.med.ecu.edu
Shibley
I A
IA
Miles
D S
DS
Pennington
J S
JS
Pennington
S N
SN
D000818:Animals; D015415:Biomarkers; D001921:Brain / Q000196:embryology*; D002462:Cell Membrane / Q000378:metabolism; D002642:Chick Embryo; D003847:Deoxyglucose / Q000493:pharmacokinetics; D004625:Embryo, Nonmammalian / Q000166:cytology / Q000187:drug effects / Q000378:metabolism / Q000502:physiology; D004798:Enzymes / Q000378:metabolism; D000431:Ethanol / Q000494:pharmacology*; D051272:Glucose Transporter Type 1; D051274:Glucose Transporter Type 3; D007425:Intracellular Membranes / Q000378:metabolism*; D009004:Monosaccharide Transport Proteins / Q000235:genetics / Q000378:metabolism*; D009419:Nerve Tissue Proteins; D012333:RNA, Messenger / Q000378:metabolism; D014018:Tissue Distribution / Q000187:drug effects
D015415:Biomarkers; D004798:Enzymes; D051272:Glucose Transporter Type 1; D051274:Glucose Transporter Type 3; D009004:Monosaccharide Transport Proteins; D009419:Nerve Tissue Proteins; D012333:RNA, Messenger; D000431:Ethanol; D003847:Deoxyglucose