The correlation between histophotometrical and biochemical myosin-ATPase measurements in the myocardium and striated muscle of the rat.

To prove the correlation between histophotometrical and biochemical data of myosin-ATPase-activity, the change of enzyme activity during development was measured in the myocardium, masseter muscle, and tensor fasciae latae of rats. Both methods were applied to the same material. To avoid errors due to varying section thickness in each cutting and staining procedure, a reference material (e.g. heart muscle) was used, taken from one and the same animal. The correlation between histophotometrical and biochemical estimations was very good, histophotometrical arbitrary units being used. ATPase-activity in heart muscle during development, slightly decreases in masseter muscle and more in tensor fasciae latae. The ATPase-activity in the latter was higher than in masseter muscle. This is in good agreement with the physiological, biochemical, and histochemical classification.