The effects of endurance exercise stress on the oxidative capacity of skeletal muscle of the streptozotocin diabetic rodent

Young female Sprague-Dawley rats ( 50 gm., body weight-BW) were conditioned to treadmill activity (13.4 m•min -1; 0% grade) over a 12 d. period and then randomly assigned to groups combining exercise (E) and diabetes (D) with appropriate normal-sedentary controls (Sd). The diabetic condition was induced by I.V. injection of Streptozotocin (70 mg/kg BW) in citrate buffer and was evidenced by hyperglycemia (>330 mg. glucose/dl), polyuria and polydipsia. The E program was conducted 6 d./wk. Intensity and duration were progressively increased and reached 20% grade at 26.8 m•min-1 with 45 sec. sprints at 40.2 m-min-1 at 5 min. intervals. Total daily E time reached 60 min. for 8 wks. of training at which time experimental and appropriate control animals were sacrificed. Paramenters studied included in vitro capacity of slow oxidative (SO), fast oxidative. glycolytic (FOG), and fast glycolytic (FG) tissues to oxidize (Q02) pyruvate and palmitate. A 2x2 factorial ANOVA was used to detect E/Sd (Factor A) effects, D/non-D (Factor B) effects, and interaction (AxB) effects. A Student-Newman-Keuls multiple range test was employed to determine which experimental groups differed from each other. Results indicate a complex interaction of treatment effects depending upon muscle type. For the most part, E resulted in a reduction or modification of U effects. The DE group was not significantly different from either Sd or E controls for pyruvate 002 for all 3 muscle types. However, DS was significantly depressed below DE and controls for SO and FG tissues (pyruvate Q02). For palmitate 002 DE was significantly greater than both DSd and CSd groups for FOG tissue, (3244μ a 02/hr./gm vs. 2538 and 2555μl 02/hr/gm). Also both DE and CE were greater than both Sd groups for FG tissue (1925 and 1664μl 02/hr/gm vs. 1352 and 1283μ1 02/hr/gm, respectively). There were no significant differences between groups for SO tissue (palmitate Q02).Thesis (M.A.