Localization and regulation of GLUTx1 glucose transporter in the hippocampus of streptozotocin diabetic rats.
We describe the localization of the recently identified glucose transporter GLUTx1 and the regulation of GLUTx1 in the hippocampus of diabetic and control rats. GLUTx1 mRNA and protein exhibit a unique distribution when compared with other glucose transporter isoforms expressed in the rat hippocampus. In particular, GLUTx1 mRNA was detected in hippocampal pyramidal neurons and granule neurons of the dentate gyrus as well as in nonprincipal neurons. With immunohistochemistry, GLUTx1 protein expression is limited to neuronal cell bodies and the most proximal dendrites, unlike GLUT3 expression that is observed throughout the neuropil. Immunoblot analysis of hippocampal membrane fractions revealed that GLUTx1 protein expression is primarily localized to the intracellular compartment and exhibits limited association with the plasma membrane. In streptozotocin diabetic rats compared with vehicle-treated controls, quantitative autoradiography showed increased GLUTx1 mRNA levels in pyramidal neurons and granule neurons; up-regulation of GLUTx1 mRNA also was found in nonprincipal cells, as shown by single-cell emulsion autoradiography. In contrast, diabetic and control rats expressed similar levels of hippocampal GLUTx1 protein. These results indicate that GLUTx1 mRNA and protein have a unique expression pattern in rat hippocampus and suggest that streptozotocin diabetes increases steady-state mRNA levels in the absence of concomitant increases in GLUTx1 protein expression.
Harold and Margaret Milliken Hatch Laboratory of Neuroendocrinology, The Rockefeller University, 1230 York Avenue, New York, NY 10021, USA. reaganl@rockvax.rockefeller.edu
L P
LP
Reagan
N
N
Gorovits
E K
EK
Hoskin
S E
SE
Alves
E B
EB
Katz
C A
CA
Grillo
G G
GG
Piroli
B S
BS
McEwen
M J
MJ
Charron
D000818:Animals; D001345:Autoradiography; D003921:Diabetes Mellitus, Experimental / Q000378:metabolism*; D005786:Gene Expression Regulation; D051246:Glucose Transport Proteins, Facilitative; D006624:Hippocampus / Q000378:metabolism*; D007150:Immunohistochemistry; D008297:Male; D009004:Monosaccharide Transport Proteins / Q000235:genetics / Q000378:metabolism*; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D013311:Streptozocin
D051246:Glucose Transport Proteins, Facilitative; D009004:Monosaccharide Transport Proteins; D009419:Nerve Tissue Proteins; D012333:RNA, Messenger; C498629:Slc2a8 protein, rat; D013311:Streptozocin