Unaltered aerobic power and endurance following glucocorticoidinduced muscle atrophy

Autor: CAPACCIO, JUDITH A., GALASSI, THOMAS M., HICKSON, ROBERT C.
Zdroj: Medicine & Science in Sports & Exercise; June 1985, Vol. 17 Issue: 3 p380-384, 5p
Abstrakt: The present study was undertaken to evaluate whether the muscle atrophy associated with glucocorticoid excess results in a reduction in maximal oxygen uptake (O2max) and endurance during exercise. Female rats were administered single subcutaneous injections of cortisone acetate (CA) (100 mg.kg-1b.w.) or the vehicle (1 carboxymethyl cellulose) for 14 consecutive days. The weights of plantaris muscles (which were used as a marker of the atrophy) of CA-treated rats were 27 less than those of plantaris muscles in the vehicle-treated rats. This condition also produced a 12-fold increase in free serum glucocorticoid concentrations (cortisol) but did not alter serum androgen (testosterone) levels. Peak O2(ml.kg-1.min-1) and endurance were greater in CA-treated vs vehicle-treated animals; however, these effects were shown to be a function of body weight loss. Homogenate oxygen uptakes in the presence of pyruvate or palmitate were also similar in slow-twitch soleus, fast-twitch red vastus, and fast-twitch white vastus lateralis muscles between CA- and vehicle-treated groups. These data provide no evidence to demonstrate that the catabolic actions of glucocorticoids in skeletal muscle result in a decrement in work capacity through at least 14 d of treatment.
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