Use of plasma creatine kinase pharmacokinetics to estimate the amount of excercise-induced muscle damage in Beagles.
OBJECTIVE
To assess the effects of moderate exercise on plasma creatine kinase (CK) pharmacokinetics and to estimate exercise-induced muscle damage in dogs.


METHODS
6 untrained adult Beagles.


METHODS
The study was divided into 3 phases. In phase 1, dogs ran for 1 hour at a speed of 9 km/h, and samples were used to determine the area under the plasma CK activity versus time curve (AUC) induced by exercise. In phases 2 and 3, pharmacokinetics of CK were calculated in dogs during exercise and at rest, respectively. Values for AUC and plasma clearance (CI) were used to estimate muscle damage.


RESULTS
At rest, values for Cl, steady-state volume of distribution (Vdss), and mean retention time (MRT) were 0.32+/-0.02 ml/kg of body weight/min, 57+/-173 ml/kg, and 3.0+/-0.57 h, respectively. During exercise, Cl decreased significantly (0.26+/-0.03 ml/kg/min), MRT increased significantly, (4.4+/-0.97 h), and Vdss remained unchanged. Peak of plasma CK activity (151+/-58.8 U/L) was observed 3 hours after completion of exercise. Estimated equivalent amount of muscle corresponding to the quantity of CK released was 41+/-29.3 mg/kg.


CONCLUSIONS
These results revealed that exercise had a minor effect on CK disposition and that the equivalent amount of muscle damaged by moderate exercise was negligible. This study illustrates the relevance for use of the minimally invasive and quantitative pharmacokinetic approach when estimating muscle damage.
Chanoit
G P
GP
Unité Mixte de Recherche 181 Physiopathologie et Toxicologie Experimentales, Institut National de la Recherche Agronomique, National Veterinary School, Toulouse, France.
Lefebvre
H P
HP
Orcel
K
K
Laroute
V
V
Toutain
P L
PL
Braun
J P
JP
D000818:Animals; D019540:Area Under Curve; D003402:Creatine Kinase / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics*; D004285:Dogs / Q000097:blood* / Q000502:physiology; D005260:Female; D008297:Male; D018482:Muscle, Skeletal / Q000293:injuries / Q000378:metabolism / Q000473:pathology*; D010805:Physical Conditioning, Animal / Q000009:adverse effects / Q000502:physiology*
D003402:Creatine Kinase