Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0015672 (fatigue)
 51,768 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The purpose of this study was to investigate whether continuous infusion of an anabolic steroid, stanozolol, would alter skeletal muscle size and performance in sedentary male mice. The study was performed as a preliminary to an investigation on the effect of anabolic steroids on skeletal muscle regeneration in the mdx mouse, an animal model used for the study of Duchenne muscular dystrophy. Skeletal muscle structure and contractile behavior, and heart, liver, kidney, and testis wet weights were assessed after 3 or 6 wk of continuous exposure to one of two concentrations of stanozolol. Continuous release pellets containing either a high (1.5 mg) or low (0.5 mg) concentration of stanozolol were implanted into 8-wk-old C57BL/6J male mice. Control mice were implanted with pellets containing the drug vehicle. Stanozolol infusion had no significant effect on the contractile strength or mass of either fast-twitch extensor digitorum longus or slow-twitch soleus muscle. The resistance to fatigue of both muscles, assessed in vitro, was unaffected by stanozolol; however, postfatigue recovery of soleus twitch and tetanic tension after 3 wk of treatment was significantly (P < 0.05) increased in high-dose mice compared with control and low-dose mice. Androgen-sensitive muscles, bulbocavernosus and levator ani, were significantly (P < 0.05) increased in wet weight after 3 wk of stanozolol treatment, but were not significantly different from control muscles after 6 wk, suggesting that continuous infusion produced a tolerance to the drug. Similarly, heart wet weight was significantly (P < 0.05) increased in stanozolol-treated mice compared with control after 3 wk, but not after 6 wk. Testis wet weight was significantly (P < 0.05) decreased in low-dose mice compared with control mice at 3 wk, but not at 6 wk. Plasma testosterone concentration was not significantly different between any of the groups after 3 or 6 wk of treatment. This study suggests that in the absence of other factors (e.g., high-intensity exercise or other degenerative changes in muscle fibers), continuous infusion of an anabolic steroid produces no significant effect on the growth, contractile strength, or endurance of hindlimb skeletal muscles.
 ...
PMID:Effect of continuous infusion of an anabolic steroid on murine skeletal muscle. 847 3

Testosterone and its synthetic derivatives anabolic-androgenic steroids have been shown to increase skeletal muscle work capacity and fatigue resistance, but the molecular basis for these effects remains uncertain. Since muscle performance has been related to redox status of exercising muscles, this investigation was aimed at testing whether a treatment with suprapharmacological doses of the anabolic-androgenic steroid stanozolol, (2 mg/kg body weight, 5 days/week, for 8 weeks), either alone or in conjunction with treadmill training (12 weeks), enhanced antioxidant defences in rat muscles. Stanozolol treatment did not modify thiobarbituric acid reactive substances and glutathione content in soleus and extensor digitorum longus (EDL) homogenates. In soleus from sedentary rats, superoxide dismutase and glutathione reductase activities were increased by 25% (P < 0.05) and by 40% (P < 0.01) after stanozolol administration, whereas catalase and glutathione peroxidase activities were not modified. This response was similar to that induced by training alone. In EDL from sedentary rats, stanozolol increased only superoxide dismutase activity (20%, P < 0.05). In no case, the effects of steroid administration and training were additive. HSP72 levels were up-regulated in soleus (1.5-fold, P < 0.01) and EDL (threefold, P < 0.001) following training but remained unchanged after stanozolol treatment. Endurance capacity, assessed in a treadmill endurance test, was similar for treated and control rats. We conclude that stanozolol treatment increases antioxidant capacity in selected skeletal muscles from sedentary rats. However, the steroid was not effective in improving endurance capacity or enhancing the training effects on muscle antioxidant defence systems.
 ...
PMID:Prolonged treatment with the anabolic-androgenic steroid stanozolol increases antioxidant defences in rat skeletal muscle. 2048 Feb 77

Anabolic androgenic steroids are used in the sport context to enhance muscle mass and strength and to increase muscle fatigue resistance. Since muscle fatigue has been related to oxidative stress caused by an exercise-linked reactive oxygen species (ROS) production, we investigated the potential effects of a treatment with the anabolic androgenic steroid stanozolol against oxidative damage induced on rat skeletal muscle mitochondria by an acute bout of exhaustive exercise. Mitochondrial ROS generation with complex I- and complex II-linked substrates was increased in exercised control rats, whereas it remained unchanged in the steroid-treated animals. Stanozolol treatment markedly reduced the extent of exercise-induced oxidative damage to mitochondrial proteins, as indicated by the lower levels of the specific markers of protein oxidation, glycoxidation, and lipoxidation, and the preservation of the activity of the superoxide-sensitive enzyme aconitase. This effect was not due to an enhancement of antioxidant enzyme activities. Acute exercise provoked changes in mitochondrial membrane fatty acid composition characterized by an increased content in docosahexaenoic acid. In contrast, the postexercise mitochondrial fatty acid composition was not altered in stanozolol-treated rats. Our results suggest that stanozolol protects against acute exercise-induced oxidative stress by reducing mitochondrial ROS production, in association with a preservation of mitochondrial membrane properties.
 ...
PMID:Stanozolol treatment decreases the mitochondrial ROS generation and oxidative stress induced by acute exercise in rat skeletal muscle. 2116 55