Glucose uptake and metabolic stress in rat muscles stimulated electrically with
different protocols.
Aslesen, Rune, Ellen M. L. Engebretsen, Jesper Franch, and Jřrgen Jensen.
1Department of Anatomy, Institute of Basic Medical Sciences, University of Oslo, N-
0317 Oslo; 2The Norwegian University of Sport and Physical Education, N-0806 Oslo;
3Department of Physiology, National Institute of Occupational Health, N-0033 Oslo,
Norway; and 4Institute of Sport Science and Physical Education, Odense University, DK-
5230 Odense, Denmark
APStracts 8:0300A, 2001.
In the present study, the relationship between pattern of electrical stimulation and glucose
uptake was investigated in a slow-twitch muscles (soleus) and fast-twitch muscles
(epitrochlearis) from Wistar rats. Muscles were stimulated electrically for 30 min in vitro
with either single pulses (frequencies varied between 0.8 and 15 Hz) or with 200-ms
trains (0.1-2 Hz). Glucose uptake (measured with tracer amount of 2-[3H]deoxyglucose)
increased with increasing number of impulses whether delivered as single pulses or as
short trains. The highest glucose uptake achieved with short tetanic contractions was
similar in soleus and epitrochlearis (10.9 ± 0.7 and 12.0 ± 0.8 mmol«chemp»kg dry
wt«minus»1«chemp»30 min«minus»1, respectively). Single pulses, on the other hand,
increased contraction-stimulated glucose uptake less in soleus than in epitrochlearis (7.5
± 1.1 and 11.7 ± 0.5 mmol«chemp»kg dry wt«minus»1«chemp»30 min«minus»1,
respectively; P < 0.02). Glucose uptake correlated with glycogen breakdown in soleus
(r = 0.84, P < 0.0001) and (epitrochlearis: r = 0.91, P < 0.0001). Contraction-
stimulated glucose uptake also correlated with breakdown of ATP and PCr and with
reduction in force. Our data suggest that metabolic stress mediates contraction-stimulated
glucose uptake.
Received 30 November 2000; accepted in final form 17 May 2001
APS Manuscript Number A1141-0.
Article publication pending J Appl Physiol
ISSN 1080-4757 Copyright 2001 The American Physiological Society.
Published in APStracts on 18 June 2001