Journal of Applied Physiology, Vol 74, Issue 4 1755-1760, Copyright © 1993 by American Physiological Society
Exercise reduces muscle glucose transport protein (GLUT-4) mRNA in type 1 diabetic patients
V. A. Koivisto, R. E. Bourey, H. Vuorinen-Markkola and L. Koranyi
Second Department of Medicine, Helsinki University Hospital, Finland.
We examined the effect of acute exercise on muscle glucose transporter
(GLUT-4) protein and mRNA concentrations in nine male type 1 diabetic
patients (age 31 +/- 3 yr, body mass index 23.6 +/- 0.7 kg/m2, insulin dose
44 +/- 4 U/day, glycosylated hemoglobin 7.8 +/- 0.4%) and in nine healthy
control subjects (34 +/- 1 yr, 25.3 +/- 0.8 kg/m2). Three hours of cycle
ergometer exercise was performed after an overnight fast. A needle biopsy
(100-150 mg) was taken from the quadriceps femoris 40 min before and
immediately after the end of exercise. During exercise, plasma glucose,
insulin, cortisol, and growth hormone concentrations were higher in the
diabetic patients than in the control subjects. In the basal state, GLUT-4
protein and mRNA concentrations were similar in the two groups. During
exercise, GLUT-4 mRNA concentration decreased by 30-45% in the diabetic
patients but remained unchanged in the control subjects. GLUT-4 protein
content remained unchanged in both groups. These data suggest an abnormal
GLUT-4 mRNA production or degradation or both in type 1 diabetic patients
during physical exercise.
