Reduced content and preserved translocation of glucose transporter (GLUT 4) in white adipose tissue of obese mice.
We investigated glucose transporters (GLUT 1 and GLUT 4) in subcellular membrane fractions of white adipose tissue (WAT) of insulin-resistant obese aurothioglucose (AuTG)- or monosodium glutamate (MSG)-treated mice. In vivo insulin stimulation (0.75 U/kg, EV) promoted, 10 min later, no significant change on glycemia of both AuTG and MSG obese mice, but control mice showed a decrease of 30% (p < 0.001). Basal GLUT 4 content in WAT of obese mice was reduced by 40% (p < 0.001) when compared to that of nonobese mice. Insulin-stimulated GLUT 4 content was significantly (p < 0.01) higher in plasma membrane fraction and lower in microsomal fraction when compared to respective basal values, in all groups. Although the absolute values of GLUT 4 were lower in membrane fractions of obese mice, the relative changes stimulated by insulin were similar among the groups. No effect of obesity or insulin stimulation was observed upon GLUT 1 content. We conclude that WAT of insulin-resistant obese AuTG- and MSG-treated mice has a decreased GLUT 4, but not GLUT 1, content, and the in vivo insulin-stimulated GLUT 4 translocation is preserved.
Machado
U F
UF
Department of Physiology and Biophysics, University of São Paulo, Brazil.
Shimizu
I
I
Saito
M
M
D000273:Adipose Tissue / Q000187:drug effects / Q000378:metabolism*; D000818:Animals; D000831:Animals, Newborn; D006051:Aurothioglucose; D001786:Blood Glucose / Q000378:metabolism; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D005260:Female; D051272:Glucose Transporter Type 1; D051275:Glucose Transporter Type 4; D007031:Hypothalamus / Q000187:drug effects / Q000503:physiopathology; D007279:Injections, Subcutaneous; D007328:Insulin / Q000097:blood; D007425:Intracellular Membranes / Q000187:drug effects / Q000378:metabolism; D008297:Male; D051379:Mice; D008820:Mice, Obese; D009004:Monosaccharide Transport Proteins / Q000378:metabolism*; D009124:Muscle Proteins; D009765:Obesity / Q000139:chemically induced / Q000378:metabolism*; D011247:Pregnancy; D012970:Sodium Glutamate; D013347:Subcellular Fractions / Q000187:drug effects / Q000378:metabolism
D001786:Blood Glucose; D051272:Glucose Transporter Type 1; D051275:Glucose Transporter Type 4; D007328:Insulin; D009004:Monosaccharide Transport Proteins; D009124:Muscle Proteins; C495678:Slc2a1 protein, mouse; C495693:Slc2a4 protein, mouse; D006051:Aurothioglucose; D012970:Sodium Glutamate