Insulin resistance and the alterations of glucose transporter-4 in adipose cells from cachectic tumor-bearing rats.
BACKGROUND
Insulin resistance may play an important role in cancer cachexia; however, its mechanisms remain to be clarified.


METHODS
Cellular mechanisms of insulin resistance in tumor-bearing rats (TBR) were investigated in isolated adipose cells by measuring 3-O-[14C]methyl glucose transport activity and glucose transporter-4 (GLUT4) protein in low-density microsomes at a basal state and in the plasma membrane at an insulin-stimulated state.


RESULTS
The insulin-stimulated glucose transport activity in adipose cells from TBR was significantly lower than that of control rats (CTR) (0.51 +/- 0.25 and 2.27 +/- 0.11 fmol/cell/min, respectively). The amount of GLUT4 in low-density microsomes at a basal state and in plasma membrane at an insulin-stimulated state was less in TBR than in CTR.


CONCLUSIONS
These data suggest that the insulin resistance seen in the adipose cells of these tumor-bearing rats was caused in part by both a decreased amount of GLUT4 protein in a basal state and a decreased translocation of GLUT4 in response to insulin stimulation.
Yoshikawa
T
T
First Department of Surgery, Yokohama City University, School of Medicine, Japan.
Noguchi
Y
Y
Satoh
S
S
Doi
C
C
Okamoto
T
T
Nomura
K
K
Makino
T
T
Tsuburaya
A
A
Matsumoto
A
A
D017667:Adipocytes / Q000378:metabolism*; D000818:Animals; D001835:Body Weight; D002100:Cachexia / Q000209:etiology / Q000378:metabolism / Q000503:physiopathology*; D002462:Cell Membrane / Q000378:metabolism; D015972:Gene Expression Regulation, Neoplastic; D005947:Glucose / Q000378:metabolism; D051275:Glucose Transporter Type 4; D066298:In Vitro Techniques; D007328:Insulin / Q000494:pharmacology; D007333:Insulin Resistance; D008297:Male; D008861:Microsomes / Q000378:metabolism; D009004:Monosaccharide Transport Proteins / Q000235:genetics / Q000378:metabolism*; D009124:Muscle Proteins; D051381:Rats; D011916:Rats, Inbred F344; D012513:Sarcoma, Experimental / Q000150:complications / Q000378:metabolism / Q000503:physiopathology*
D051275:Glucose Transporter Type 4; D007328:Insulin; D009004:Monosaccharide Transport Proteins; D009124:Muscle Proteins; C495694:Slc2a4 protein, rat; D005947:Glucose