Journal of Applied Physiology, Vol 50, Issue 2 245-249, Copyright © 1981 by American Physiological Society
Fibrinolytic activity without fibrinogenolysis during long-distance racing in horses
E. W. Ferguson, L. L. Bernier, G. P. Shaughness and J. H. Boucher
Fourteen horses were studied during a 157-km endurance ride. Two humans who
ran the 157 km were also evaluated at the finish. Fibrin monomer samples
were examined by two-dimensional gel electrophoresis and sodium dodecyl
sulfate polyacrylamide gel electrophoresis. Two major species of horse
Beta-chain with higher molecular weights and different isoelectric
mobilities than human beta-chain were observed. Horse alpha-chains had
higher molecular weights than human alpha-chains but similar alpha-chain
heterogeneities. Mean euglobulin lysis time (ELT) in the horses was
accelerated to similar levels throughout the ride (52% of control at 44 km,
P less than 0.01), but mean plasma clot lysis time (PCLT) decreased
progressively during the ride (30% of control at finish, P less than
0.005). Similar values for ELTs and PCLTs were noted in the runners and
horses at the finish. Although fibrinolytic activity was accelerated for an
extended period by the strenuous activity of this long-distance race, no
evidence of increased carboxyl terminal degradation of the A alpha-chain
was observed. This study suggests that prolonged physiological stimulation
of the fibrinolytic enzyme (plasmin) system is not responsible for
fibrinogen A alpha-chain heterogeneities observed in horses and humans. It
further demonstrates the usefulness of horses as models for the study of
exercise-induced fibrinolysis.
