COMPARED KINETICS OF PLASMA CREATINE-KINASE ACTIVITY IN RABBITS AFTERINTRAVENOUS-INJECTION OF DIFFERENT PREPARATIONS OF SKELETAL-MUSCLE

The purpose of this study was to compare the disposition parameters of creatine kinase (CK) in rabbits after intravenous bolus administratio n of 3 CK preparations: 1) purified CK; 2) CK obtained from a muscular extract after a 3 000 g centrifugation tie with cell remains) (3 000 g CK); or 3) a 105 000 g centrifugation tie the cytosolic soluble phas e) (105 000 g CK). The plasma half-lives were not significantly differ ent (approximate to 9 h). In contrast, the clearance of 3 000 g CK (3. 25 +/- 0.33 ml.kg(-1).h(-1)) was significantly lower than that of the 2 others (7.00 +/- 0.49 ml.kg(-1).h(-1) and 4.63 +/- 0.65 ml.kg(-1).h( -1) for 105 000 g and purified CK, respectively). These findings sugge st that purified CK preparation is not the most appropriate form for d etermination of enzyme pharmacokinetic parameters following muscle dam age.