Lactate transport studied in sarcolemmal giant vesicles from rat
skeletal muscles: effect of denervation.
Pilegaard, Henriette, and Carsten Juel.
Copenhagen Muscle Research Centre, August Krogh Institute,
University of Copenhagen, Denmark
APStracts 2:0104E, 1995.
The effect of denervation on lactate transport capacity was studied in
giant sarcolemmal vesicles obtained from rat muscle. The rate of
lactate transport was determined in soleus, red (RG) and white (WG)
gastrocnemius after 1, 3 and 21 days of denervation and in the
corresponding contralateral muscles. In addition, muscle lactate
dehydrogenase (LDH) and succinate dehydrogenase (SDH) activities were
determined. After 1, 3 and 21 days of denervation the rate of lactate
transport was lower (P<0.05) in WG (9, 11 and 36%), RG (15, 22 and
41%) and soleus (10, 24 and 50%) compared with the contralateral
muscles. After 21 days of denervation LDH-activity was 20, 21 and 40%
and SDH-activity 31, 40 and 27% lower (P<0.05) in WG, RG and
soleus, respectively, compared with the contralateral muscles. In the
control muscles the lactate transport capacity was 18 and 29% lower
(P<0.05) in WG than in RG and soleus, respectively. The present
findings support that the sarcolemmal lactate carrier is a plastic
system; the transport capacity in soleus, RG and WG declines already
after 1 day of denervation and is further reduced after 21 days of
denervation. In addition, the data suggest that the lactate transport
capacity in fast-twitch glycolytic fibers < fast-twitch oxidative
glycolytic fibers < slow-twitch oxidative fibers.
Received 15 March 1995; accepted in final form 9 May 1995.
APS Manuscript Number E118-5.
Article publication pending Am. J. Physiol. (Endocrinol. Metab.).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 26 May 1995.