The purpose of this study was to determine whether muscle hypertrophy occurs in diabetic rats in response to resistance exercise. Male Sprague Dawely rats performed resistance exercise by repeated standing on the hindlimbs with weighted backpacks. Diabetic(partial pancreatectomy) or nondiabetic rats performed progressive resistance exercise for 8 weeks or remained sedentary (sed). Arterial plasma insulin in the diabetic groups were reduced by about half (p<0.05) when compared to the nondiabetic groups. Soleus(sol) and gastrocnemius/plantaris (gast/plant) complex muscle wet weights were lower due to diabetes but in response to chronic exercise these muscles hypertrophied in diabetic(soleus: 0.28±.03 sed vs 0.32±.015 ex; gast/plant 0.42±.068 sed vs 0.53±0.041 ex both p<0.05) but not in nondiabetic (0.41±.026 sed vs 0.42±.03 ex; 0.72±.015 sed vs. .069±.013 ex) rats when muscle weight was expressed relative to tibial length(g·cm−1) or body weight(data not shown). Rates of protein synthesis (measured using the in vivo phenylalanine flooding dose technique) were higher in red gastrocnemius of both chronically exercised diabetic(155±11 nmol phenylalanine incorporated/ g muscle / hr) and nondiabetic(170±7) rats compared to sedentary diabetic(110±14) and nondiabetic(143±7). Chronic exercise training was associated with reductions in basal glycemia and such reductions did not occur in sedentary diabetic groups. These data demonstrate that moderately diabetic rats can hypertrophy muscle in response to a physiological stimulus. Support by NIH grants: AR43127, GM39277, DK15658
American College of Sports Medicine; 46th Annual Meeting; Washington State; Convention & Trade Center; June 2-5, 1999
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E-31 POSTER ENDOCRINOLOGY II