The effect of blood flow on muscle lactate release studied in the
perfused rat hindlimb.
Pilegaard, Henriette, Jens Bangsbo, Pernille Henningsen, Carsten Juel,
and Erik A. Richter.
Copenhagen Muscle Research Centre, August Krogh Institute,
University of Copenhagen, Denmark
APStracts 2:0146E, 1995.
The influence of blood flow on muscle lactate and H+ release as well
as muscle glyconeogenesis was studied in the perfused rat hindlimb.
After 2 min of supramaximal stimulation the perfusate flow rate was
either 7 (F7), 12 (F12) or 18 (F18) ml x min-1 for 30 min. Perfusate
samples were drawn frequently and muscle samples were obtained
before, immediately after stimulation and at 3, 10 and 30 min of
recovery from soleus, white gastrocnemius (WG) and red gastrocnemius.
During the first 5 min of recovery lactate release was 35-39% lower
(P<0.05) in F7 than in F12 and F18, but with no differences in
total release during recovery. In F7 the concentration of lactate was
higher (P<0.05) in soleus after 10 min (18-20%) and in WG after
30 min (63-67%) compared with F12 and F18. During the first 2 min of
recovery H+ release was 23-34% lower (P<0.05) in F7 than in F12
and F18. The difference between H+ and lactate release was larger
(P<0.05) in F7 than in F12 and F18 from 3 to 10 min and from 5
to 10 min of recovery, respectively. Muscle glycogen concentrations
after 30 min of recovery were independent of flow in each of the
muscles. The present data suggest that 1) in the range of blood flow
rates from 0.61 to 0.92 ml x min-1 x g-1 lactate and H+ release are
independent of the flow rate, whereas at a lower flow rate (0.36 ml x
min-1 x g-1) release of these substances is decreased; 2) low blood
flow influences lactate efflux more than H+ release; 3) muscle
glyconeogenesis from lactate is small.
Received 1 February 1995; accepted in final form 27 June 1995.
APS Manuscript Number E45-5.
Article publication pending Am. J. Physiol. (Endocrinol. Metab.).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 18 July 1995.