Influence of exercise and Dianabol on the degradation rate of myofibrillar proteins of the heart and three fiber types of skeletal muscle of female guinea pigs.

The influence of methandrostenolone (= Dianabol = 17-beta-hydroxy-17-methylandrosta-1,4-dien-3-one) and of a running training program on the degradation rate of myofibrillar proteins of the heart, soleus, red portion of the vastus lateralis, and white portion of the vastus lateralis of female guinea pigs was studied by measuring the time-dependent decrease of radioactive-labeled proteins. The following results were obtained: No alteration of absolute muscle or body weight An increased heart-to-body weight relation in the trained and in the trained group receiving Dianabol A significantly higher myofibrillar protein concentration in the skeletal muscle types than in the heart An increased concentration of myofibrillar proteins in all muscle types in the trained group receiving Dianabol and in the heart of the untrained group receiving Dianabol The degradation rate of the myofibrillar proteins decreased in all muscle types in the trained group receiving Dianabol and in the heart of the untrained group receiving Dianabol and in the trained group.