title: Effect of in vivo injection of cholera and pertussis toxin on glucose transport in rat skeletal muscle.
abstract: Cholera toxin (CTX) and pertussis toxin (PTX) were examined for their ability to inhibit glucose transport in perfused skeletal muscle. Twenty-five hours after an intravenous injection of CTX, basal transport was decreased approximately 30%, and insulin- and contraction-stimulated transport was reduced at least 86 and 49%, respectively, in both the soleus and red and white gastrocnemius muscles. In contrast, PTX treatment was much less efficient. Impairment of glucose transport appeared to develop 10-15 h after CTX administration, which coincided with development of hyperglycemia despite hyperinsulinimia, increased plasma free fatty acid levels, increased adenosine 3',5'-cyclic monophosphate (cAMP) concentrations in muscle, but no difference in plasma catecholamines. Twenty-five hours after CTX treatment, GLUT-4 protein in both soleus and red gastrocnemius muscles was decreased, whereas no change in GLUT-1 protein content was found. In contrast, GLUT-4 mRNA was unchanged, but transcripts for GLUT-1 were increased > or = 150% in all three muscles from CTX-treated rats. The findings suggest that CTX via increased cAMP impairs basal as well as insulin- and contraction-stimulated muscle glucose transport, at least in part from a decrease in intramuscular GLUT-4 protein.
authors.affiliation: Department of Medical Physiology, Panum Institute, University of Copenhagen, Denmark.
authors.forename: T
authors.initials: T
authors.lastname: Ploug
authors.forename: X
authors.initials: X
authors.lastname: Han
authors.forename: L N
authors.initials: LN
authors.lastname: Petersen
authors.forename: H
authors.initials: H
authors.lastname: Galbo
mesh_terms: D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D002395:Catecholamines / Q000378:metabolism; D002772:Cholera Toxin / Q000494:pharmacology*; D000242:Cyclic AMP / Q000378:metabolism; D005947:Glucose / Q000378:metabolism*; D051272:Glucose Transporter Type 1; D051275:Glucose Transporter Type 4; D007275:Injections, Intravenous; D007328:Insulin / Q000494:pharmacology; D008297:Male; D009004:Monosaccharide Transport Proteins / Q000235:genetics / Q000378:metabolism; D009119:Muscle Contraction / Q000502:physiology; D009124:Muscle Proteins; D018482:Muscle, Skeletal / Q000378:metabolism*; D037342:Pertussis Toxin; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D010566:Virulence Factors, Bordetella / Q000494:pharmacology*
chemical_list: D002395:Catecholamines; D051272:Glucose Transporter Type 1; D051275:Glucose Transporter Type 4; D007328:Insulin; D009004:Monosaccharide Transport Proteins; D009124:Muscle Proteins; D012333:RNA, Messenger; C495679:Slc2a1 protein, rat; C495694:Slc2a4 protein, rat; D010566:Virulence Factors, Bordetella; D002772:Cholera Toxin; D000242:Cyclic AMP; D037342:Pertussis Toxin; D005947:Glucose