Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.3.3.1 (citrate synthase)
 4,488 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The influence of training adaptations, induced within the active muscles of rats with peripheral arterial insufficiency, was assessed with an isolated hindlimb preparation. Femoral artery-stenosed rats, showing symptoms of intermittent claudication, were trained for 14-20 wk by running at 20-35 m/min up a 15% grade for up to approximately 1 h/day, 5 days/wk. Similar total hindlimb blood flows (12.6 ml/min) at a similar arterial O2 content (20.7 vol/100 ml) yielded similar blood flows (95-117 ml.min-1.100 g-1) and O2 deliveries (9-11 mumol.min-1.g-1) to the contracting muscle of sedentary (n = 10) and trained (n = 10) rats. Ten-minute periods of tetanic contractions (100 ms at 100 Hz each) at 4, 8, 13, 45, 60, and 90 tetani/min were used. Muscle force development was better maintained (P less than 0.001) by the trained group. Higher peak O2 consumption (P less than 0.01) of the trained (5.69 +/- 0.53 mumol.min-1.g-1) compared with the sedentary group (3.66 +/- 0.26 mumol.min-1.g-1) involved a greater O2 extraction, since delivery of O2 was not different between groups. Thus adaptations occurred within trained muscle to enhance performance and peak O2 consumption. Muscle citrate synthase activity, an index of mitochondrial content, was greater (P less than 0.005) in the trained group, with the low-oxidative white muscle section exhibiting the greatest change (approximately threefold sedentary). Adaptations in this section were probably realized functionally, since improvements in muscle performance were evident early in the contraction sequence.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Muscle adaptations in trained rats with peripheral arterial insufficiency. 199 87

1. The activities of phosphofructokinase (PFK), citrate synthetase (CS), lactate dehydrogenase (LDH), 3-hydroxyacyl-CoA dehydrogenase (ACDH) and cytochrome-c oxidase(Cyt-ox) in the calf muscle tissue were compared in subjects with intermittent claudication (n = 38) and controls (n = 20). The activities of CS, ACDH and Cyt-ox were increased and the activity of Cytox was positively correlated to the maximal walking distance (MWD) in the patients. 2. Thirty-three patients with intermittent claudication were randomized to three treatment groups: (1) operative surgery, (2) operative surgery supplemented with physical training and (3) physical training alone. Before and after 6-12 months of treatment, symptom-free walking distance (SFWD), MWD, ankle-brachial blood pressure quotient (ankle index), maximal plethysmographic calf blood flow (MPBF) and the activities of PFK, CS, LDH, ACDH and Cyt-ox were measured. 3. SFWD and MWD increased in all three groups. Ankle index and MPBF increased in groups 1 and 2, but were unchanged in group 3. The activities of Cyt-ox and CS decreased with operation, but the activity of Cyt-ox was further augmented with training in group 3. Overall, the change in ankle index explained 80-90% of the variability in walking performance. In a separate analysis, the increased activity of Cyt-ox in group 3 was positively correlated to, and explained 31% of the variability in, the improvement in SFWD. 4. These findings indicate that both physical activity and a reduced calf blood flow are necessary conditions for the enzymatic adaptation to take place. A causal relationship between metabolic adaptation in the muscle tissue and walking performance is suggested.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Muscle enzyme adaptation in patients with peripheral arterial insufficiency: spontaneous adaptation, effect of different treatments and consequences on walking performance. 255 5