Hypertrophy of skeletal muscle in diabetic rats in response to chronic resistance exercise

Noll Physiological Research Center and Department of Kinesiology, University Park 16802; and Department of Cellular and Molecular Physiology, Pennsylvania State University College of Medicine, Hershey, Pennsylvania 17033 This study had the following objectives: 1 ) to determine whether diabetic rats could increase muscle mass due to a physiological manipulation (chronic resistance exercise), 2 ) to determine whether exercise training status modifies the effect of the last bout of exercise on elevations in rates of protein synthesis, and 3 ) to determine whether chronic resistance exercise alters basal glycemia. Groups consisted of diabetic or nondiabetic rats that performed progressive resistance exercise for 8 wk, performed acute resistance exercise, or remained sedentary. Arterial plasma insulin in diabetic groups was reduced by about one-half ( P < 0.05) compared with nondiabetic groups. Soleus and gastrocnemius-plantaris complex muscle wet weights were lower because of diabetes, but in response to chronic exercise these muscles hypertrophied in diabetic (0.028 ± 0.003 vs. 0.032 ± 0.0015 g/cm for sedentary vs. exercised soleus and 0.42 ± 0.068 vs. 0.53 ± 0.041 g/cm for sedentary vs. exercised gastrocnemius-plantaris, both P