筋組織に及ぼすPrednisoloneの影響

抄録

In daily urinary pool of rabbits, the ratio of excreted creatine to creatinine was found to have been raised by daily parenteral administration of 25 mg of Prednisolone. In these animals, urinary recovery of creatine, orally loaded, was larger than in the control. This fact shows that the creatinuria in this case does not depend on an impaired synthesis but on decreased storage capacity.
Isotope technique was used to elucidate the storage capacity. Thirty minutes after a subcutaneous injection of 2 μC (112 gamma) of C₁₄-creatine to a male albino rat, the radioactivities were found in the lungs, heart, liver, kidneys, spleen, skeletal muscles with the exception of the brain. However, a gradual increase in the radioactivities followed in the brain, heart and skeletal muscle, but a decrease in the other organs. Finally, 44 hrs after the injection, the distribution pattern of radioactivities to each tissue became identical to that of total creatine and creatine kinase.
These findings lead us to the conclusion that the creatinuria by prednisolone is due to the lowered ability of converting creatine to creatine phosphate-the fixed form in the tissues-, as a result of decrease in creatine kinase activity.
The decrease in enzyme activity was found in creatine kinase, aldolase, and Ca-ATPase of rabbit muscles by injection of prednisolone. The influence of the steroid on these enzymes is not necessarily equal in different tissues. The change was most significant in the back muscle followed by gastrocnemius, soleus, diaphragm and heart in decreasing order.
The color of the muscles was the deepest red in the heart, gradually fading in association with the decrease of myoglobin, succinic dehydrogenase activity, the ratio of GOTm to total GOT, the ratio of GPTm to total GPT, and the amount of H subunit in LDH in the above order. A composition of the heart is suitable for its tonic movement, and contrary, that of the back muscle for its phasic movement. It can be said, therefore, that the steroid exerts a stronger influence on the white color muscle with phasic movement.