4-Bromocrotonic acid enhances basal but inhibits insulin-stimulated glucose transport in 3T3-L1 adipocytes.
Inhibitors of fatty acid oxidation, 2-bromopalmitic acid (Br-C16) and 4-bromocrotonic acid (Br-C4) were examined for their effect on glucose transport in 3T3-L1 adipocytes. Whereas Br-C16 was without effect, Br-C4 augmented basal but inhibited insulin-stimulated 2-deoxyglucose uptake in a dose- and time-dependent manner. Immunoblot analysis indicated that following Br-C4 pretreatment, the content of GLUT1 in plasma membranes was increased whereas insulin-induced translocation of GLUT4 was greatly eliminated. The total cellular amount of GLUT1 or GLUT4, on the other hand, was not altered. Thus these results seem to suggest that Br-C4 has opposite effect on basal and insulin-stimulated glucose transport by a mechanism other than its inhibition of fatty acid oxidation. The translocation processes for both GLUT1 and GLUT4 transporters appears to be altered.
Leu
S J
SJ
Institute of Biochemistry, National Yang-Ming University, Taipei, Taiwan, R.O.C.
Chai
S P
SP
Kwok
C F
CF
Fong
J C
JC
D016475:3T3 Cells; D017667:Adipocytes / Q000187:drug effects / Q000378:metabolism*; D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D003437:Crotonates / Q000494:pharmacology*; D003847:Deoxyglucose / Q000378:metabolism; D004357:Drug Synergism; D005947:Glucose / Q000378:metabolism*; D051272:Glucose Transporter Type 1; D051275:Glucose Transporter Type 4; D007328:Insulin / Q000494:pharmacology*; D051379:Mice; D009004:Monosaccharide Transport Proteins / Q000502:physiology; D009124:Muscle Proteins; D010084:Oxidation-Reduction / Q000187:drug effects; D010168:Palmitates / Q000037:antagonists & inhibitors / Q000378:metabolism
D003437:Crotonates; D051272:Glucose Transporter Type 1; D051275:Glucose Transporter Type 4; D007328:Insulin; D009004:Monosaccharide Transport Proteins; D009124:Muscle Proteins; D010168:Palmitates; C495678:Slc2a1 protein, mouse; C495693:Slc2a4 protein, mouse; C034444:4-bromocrotonic acid; D003847:Deoxyglucose; D005947:Glucose