Recent evidence has shown that pulsed steroids can resynchronize cell cycling and cytokine signaling, leading to decreased inflammation after injury in an asthma cell culture model. Perhaps an optimal GC dosing schedule could help minimize inflammation, whereas other GC dosing schedule would increase it. Further studies in animal models should more closely replicate clinical dosing schedules to allow us to better assess any deleterious effects. We also assessed the overall behavioral activity of the mice using an open-field Digiscan apparatus and found that the animals adapted to the Digiscan apparatus over a period of time and generally performed better with time than they did at the initial time point. A comparison of the treatment groups clearly indicated that the GC-treated group generally showed higher behavioral activity measures when the GC was normalized to body weight in early stages of the treatment. The beneficial effects are clearly related to the loss of body weight that occurs upon GC treatment. Many of beneficial effects are Diperodon abolished by 180 days, indicating that even the normalized beneficial effects are transient. It is likely that the side effects of GC overtake the beneficial effects after prolonged GC treatment in dystrophin-deficient mice. Taken together, these data point to beneficial effects of GCs early in the period of administration but also to deleterious effects associated with chronic administration. It is generally accepted that therapy with corticosteroids improves the muscle strength of patients and benefits their ambulation, scoliosis, and respiratory function. The treatment has only engendered problems with weight gain as the principal side effect. Results similar to ours have been reported by Granchelli et al, who found that a dose of 1 mg/ kg/d of prednisone improved strength in mdx mice by 24%, whereas higher doses ranging from 5 to 20 mg/kg were deleterious. Our findings in mice point out clear differences from the human experience with GCs in DMD patients. Based on the recommendations of an international workshop in 2004, daily steroid therapy has become the “gold standard” reatment in DMD patients. These recommendations had been based on many studies that showed the benefits of steroids on skeletal and respiratory muscle function. Studies then began to focus on the cardiac effects. Silversides et al. showed that only 5% of patients treated with deflazacort for 3 or more years had a significantly decreased ejection fraction, as compared to 58% of untreated patients. They also found a correlation between preservation of cardiac Deoxycholic acid function and improvement in pulmonary and skeletal muscle function. Markham et al. found that steroid-naive subjects 10 years old or younger were 4.4 times more likely to have decreased cardiac function.