Effect of in vivo injection of cholera and pertussis toxin on
glucose transport in rat skeletal muscle.
Ploug, Thorkil, Xiaoxia Han, Lone N. Petersen# and Henrik Galbo.
Department of Medical Physiology, The Panum Institute, University
of Copenhagen; Department of Oncology, and the Copenhagen Muscle
Research Centre, Rigshospitalet, Copenhagen, Denmark
APStracts 3:0186E, 1996.
Cholera toxin (CTX) and pertussis toxin (PTX) were examined for their
ability to inhibit glucose transport in perfused skeletal muscle.
Twentyfive hours following an intravenous injection of CTX basal
transport was decreased -30%, and insulin- and contraction-stimulated
transport were reduced at least 86% and 49%, respectively, in both
the soleus, red and white gastrocnemius muscles. In contrast PTX
treatment was much less efficient. Impairment of glucose transport
appeared to develop 10-15 hours following CTX administration, which
coincided with development of hyperglycemia despite hyperinsulinimia,
increased plasma FFA levels, increased cAMP concentrations in muscle
but no difference in plasma catecholamines. Twentyfive hours after
CTX treatment GLUT4 protein in both soleus and red gastrocnemius
muscles were decreased while no change in GLUT1 protein content was
found. In contrast GLUT4 mRNA was unchanged, but transcripts for
GLUT1 were increased at least 150% in all 3 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 due to a decrease in intramuscular GLUT4
protein.
Received 16 January 1996; accepted in final form 26 August 1996.
APS Manuscript Number E17-6.
Article publication pending Am. J. Physiol. (Endocrinol. Metab.).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 19 September 1996