Creatine Phosphokinase Activity in Heart and Skeletal Muscle of Foetal Rabbits.

Abstract
Quantitative analysis of creatine phosphokinase in rabbit fetal tissue revealed that the enzyme is first detected in the heart on the 16th day of gestation and in the gastrocnemius muscle on the 23rd gestational day. There appears to be reasonable correlation between appearance of creatine phosphokinase and development of contractility in skeletal muscle but such a correlation does not exist in heart muscle.