Saddleback Journal of Biology - Saddleback College

Fall 2009 Biology 3B Paper
lactate measurement serves as a marker of
performance. The rate of lactate production in
exercising muscle is influenced by oxidative
capacity and thus training, which is often
accompanied with an increase in the number of
mitochondria, may reduce lactate production
(Poso, 2002). On top of this, horses already have
a marked increase in oxygen consumption with a
maximal oxygen uptake of about 160 mL/kg
body weight × min (Evans & Rose 1988, Rose et
al. 1988). This is more than twice the uptake in
human elite athletes (Poso, 2002). Training can
also increase the monocarboxylate transport
proteins in the sarcolemma (Poso, 2002,
Hashimoto et al., 2008, Brooks et al., 1999). This
allocates for a faster rate of facilitated diffusion
and therefore would add to the lactate
concentration. The quantity of lactic acid that is
permitted to build up is determined by the effort
that is needed to increase the lactate
concentration to levels above its resting value.
This occurs when anaerobic glycolysis produces
lactate at a greater rate than the animal’s capacity
to remove it (Gondim et al., 2007). In skeletal
muscle, the fast-twitch glycolitic fibers are
mainly producers of lactate while the slow
oxidative fibers act as consumers; and therefore
these two fibers, along with other factors, are
responsible for creating the net change in lactate
levels (Hashimoto et al., 2008).
Acknowledgements
We would like to thank the J.F. Shea
Therapeutic Riding Center for allowing us the
use of their facilities, horses, medical supplies
and time of their staff, with a special thanks to
Richard Markel, DVM. We would also like to
thank the following people for their assistance
and input towards this project: Professor Steve
Teh, and Aaron Ko.
Literature Cited
Brooks, G.A., H. Dubouchaud, M. Brown, J.P.
Sicurello, and C.E. Butz. 1999. Role of
mitochondrial lactate dehydrogenase and lactate
oxidation in the intracellular lactate shuttle.
Proceedings of the National Academy of
Sciences of the United States of America 96:
1129-1134.
Cutmore, C.M.M., D.H. Snow, and E.A.
Newsholme. 1993. Activities of key enzymes of
aerobic and anaerobic metabolism in middle
gluteal muscle from trained and untrained horses.
Equine vet. J. 17: 354-356.
Essén-Gustavsson, B., K. Karlström, and A.
Lindholm.1984. Fibre types, enzyme activities
and substrate utilization in skeletal muscles of
horses competing in endurance races. Equine vet.
J. 16: 197-202.
Evans D.L., and R.J.Rose. 1988. Determination
and repeatability of maximum oxygen uptake
and other cardio respiratory measurements in the
exercising horse. Equine
vet. J. 20: 94-98.
Gondim, J.F., C.C. Zoppi, L. P. da-Silva, and
D.V. de Macedo, 2007. Determination of
the anaerobic threshold and maximal lactate
steady state speed in equines using the lactate
minimum speed protocol. Comparative
Biochimistry and Physiology, Part A 146: 375-
380.
Hashimoto, T., R. Hussien, H.S. Cho, D. Kaufer,
and G.A. Brooks. 2008. Evidence for the
mitochondrial lactate oxidation complex in rat
neurons: demonstration of an essential
component of brain lactate shuttles. PLoS ONE
3 (8): e2915.
Henriksson, J., M.M.Y. Chi, C.S. Hintz, D.A.
Young, K.K. Kaiser, S. Salmons , O.H. Lowry.
1986. Chronic stimulation of mammalian
muscle: changes in enzyme of six metabolic
pathways. Am. J. Physiol. 251: C614-C632.
Kobayashi, M. 2007. Simple Lactate
Measurement in Horses Using a Portable Lactate
Analyzer with Lancet Skin Punctures Under
Field Conditions. Journal of Equine Science 18:
5-11.
Newsholme, EA, A.R. Leech. Biochemistry for
the Medical Sciences. Chichester, John Wiley &
Sons: 1986, pp 357-381.
Poso, A.R. 2002. Monocarboxylate transporters
and lactate metabolism in equine
athletes: a review. Acta Veterinaria
Scandinavica 43: 63-74.
Ribeiro, L., P. Balikian, P. Malachias, and V.
Baldissera. 2003. Stage length, spline function
and lactate minimum swimming speed. J. Sports
Med. Phys. Fitness 43: 312-318.
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Saddleback Journal of Biology
Spring 2010