Epinephrine administration stimulates GLUT4 translocation but reduces glucose transport in muscle.
Epinephrine opposes glucose transport in muscle. Therefore, we investigated the effects of epinephrine administration (25 micrograms/100g body weight) on glucose transport and glucose transporters in rat muscle. Ninety minutes after epinephrine injection 3-O-methyl glucose transport was reduced (approximately 47%) in perfused muscles of the rat hindlimb. Translocation of the insulin-regulatable glucose transporter (GLUT4) in the epinephrine-injected animals was confirmed by the marked increments in the GLUT-4 in the plasma membranes and their concomitant reduction in the intracellular membranes. We speculate a) that it is epinephrine which translocated GLUT4 via a cAMP-linked pathway, and b) that the intrinsic activity reductions are caused either by the glycation of the transporter by the persistent hyperglycemia and/or by epinephrine via the phosphorylation of the GLUT4 transporter protein in muscle.
Bonen
A
A
Department of Kinesiology, University of Waterloo, Ontario, Canada.
Megeney
L A
LA
McCarthy
S C
SC
McDermott
J C
JC
Tan
M H
MH
D019325:3-O-Methylglucose; D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D015153:Blotting, Western; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D004837:Epinephrine / Q000494:pharmacology*; D005947:Glucose / Q000378:metabolism*; D008297:Male; D008757:Methylglucosides / Q000378:metabolism; D009004:Monosaccharide Transport Proteins / Q000378:metabolism*; D009132:Muscles / Q000187:drug effects / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains
D008757:Methylglucosides; D009004:Monosaccharide Transport Proteins; D019325:3-O-Methylglucose; D005947:Glucose; D004837:Epinephrine