Changes in the age-depended levels of serum creatine kinase isoenzyme fractions in juvenile outpatients.

The age-depended levels of creatine kinase (CK) isoenzymes in 544 juvenile outpatients and 37 healthy adults were evaluated by CK isoenzyme analysis with cellulose acetate membrane electrophoresis. From the results, the age-depended levels of CK-MM activities were relatively low in the tested all subjects. Further, higher activities of CK-BB and CK-MB were depended on younger juveniles. In contrast, mitochondrial CK (m-CK) was detected in 511 (93.9%) of the tested 544 juveniles and in all of the tested 37 healthy adults. In addition, higher levels of m-CK were found in the tested all age groups, compared with those levels of CK-BB and CK-MB.