Nutritional regulation of glucose transporter in muscle and adipose tissue of weaned rats.
The role of glucose transporters GLUT-1 and GLUT-4 in the development of insulin sensitivity at weaning in rat skeletal muscles and adipose tissue was studied in relation to the nutritional changes when suckling rats shift from a high-fat (HF) to a high-carbohydrate (HCHO) diet. Insulin stimulated the translocation of GLUT-4 protein from an intracellular pool to the plasma membrane in adipocytes from suckling and HCHO- or HF-weaned rats. The GLUT-4 protein and the insulin stimulation were threefold higher in adipocytes from HCHO-weaned rats than in suckling or HF-weaned rats. GLUT-4 mRNA and protein were low in adipose tissue and skeletal muscles of suckling rats and increased two- to threefold in HCHO-weaned rats. This increase was prevented in HF-weaned rats. GLUT-1 mRNA was not affected in both tissues by the developmental stage or the nutritional environment. After feeding HCHO to a suckling rat, GLUT-4 mRNA was threefold increased in 6 days and reached a peak after 4 days in both tissues. The insulin sensitivity of glucose transport in rats at weaning might be conferred by an enhanced expression of GLUT-4, which can be induced within a few hours after feeding a HCHO diet.
Leturque
A
A
Centre de Recherche sur la Nutrition, Centre National de la Recherche Scientifique, Meudon-Bellevue, France.
Postic
C
C
Ferre
P
P
Girard
J
J
D000273:Adipose Tissue / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism*; D000375:Aging; D000818:Animals; D000833:Animals, Suckling; D015152:Blotting, Northern; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D002478:Cells, Cultured; D015342:DNA Probes; D004032:Diet; D004040:Dietary Carbohydrates; D004041:Dietary Fats; D006706:Homeostasis; D007328:Insulin / Q000494:pharmacology; D008861:Microsomes / Q000187:drug effects / Q000378:metabolism; D009004:Monosaccharide Transport Proteins / Q000235:genetics*; D024510:Muscle Development; D009132:Muscles / Q000378:metabolism*; D011499:Protein Processing, Post-Translational; D012333:RNA, Messenger / Q000235:genetics* / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D014886:Weaning
D015342:DNA Probes; D004040:Dietary Carbohydrates; D004041:Dietary Fats; D007328:Insulin; D009004:Monosaccharide Transport Proteins; D012333:RNA, Messenger