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

The effects of isoprenaline administration (300 micrograms/kg for 5 weeks) on rat soleus muscle capillarity and glycolytic and oxidative capacities were evaluated. The treatment resulted in ventricular hypertrophy. The activities of lactic dehydrogenase, pyruvate kinase, citrate synthase, and cytochrome c oxidase in soleus muscle homogenates were not different between control and isoprenaline-injected animals. Capillaries were visualized in muscle cross sections treated to demonstrate ATPase activity after acid preincubation. Capillary density was higher in the experimental (873 +/- 38 capillaries/mm2) than in the control (713 +/- 33 capillaries/mm2) animals. Capillary to fiber ratio was also higher in the experimental (2.47 +/- 0.10) than in control (2.09 +/- 0.08) animals, but fiber cross-sectional area was not changed by the treatment (2836 +/- 87 microns2 in controls and 2951 +/- 136 microns2 in experimental). A plot of capillary to fiber ratio vs. fiber cross-sectional area showed that at a given fiber cross-sectional area the value of capillary to fiber ratio of the treated animals was higher than that of the controls. This indicates that treatment resulted in the proliferation of microvessels. The results suggest that prolonged beta-adrenergic stimulation results in the development of new capillaries but that this is not accompanied by increases in the oxidative capacity of the soleus muscle of the rat.
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PMID:Long-term isoprenaline administration produces an increase in capillarity in the soleus muscle of the rat. 358 Sep 52

Human muscle cell cultures were examined for capacities to oxidize several substrates, and for activities of some enzymes related to intermediate metabolism. The results indicate that mitochondrial activities attained appreciable degrees of maturity. The specific activity of creatine kinase increased during myoblast fusion. In contrast, parameters of oxidative metabolism (palmitate and pyruvate oxidation, and cytochrome c oxidase and citrate synthase) did not significantly change throughout myogenesis and thereafter. In differentiated cells (myotubes) the oxidation capacities were pyruvate greater than 2-oxoglutarate greater than malate (+ acetylcarnitine) greater than malate (+ pyruvate), as in muscle biopsies. With regard to protein the cultured human muscle cells showed higher activities than the original biopsies (= 100%) with respect to citrate synthase (179%), but lower values for cytochrome c oxidase (50%) and creatine kinase (7%). Palmitate oxidation capacities were the same in both systems. The presence of antimycin and rotenon inhibited to a comparable extent the palmitate oxidation in cultured muscle and biopsies.
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PMID:Oxidative metabolism of cultured human skeletal muscle cells in comparison with biopsy material. 396 49

Soleus muscle oxidative capacity, fiber composition and capillarity were studied in rats that were injected with 300-400 micrograms/kg of triiodothyronine (T3) every other day for 28 days and then left to recover for 4, 8, 14, 21 or 28 days. The activities of cytochrome c oxidase and citrate synthase and the capacity to oxidize pyruvate plus malate of muscle homogenates were 40, 53 and 21% higher than control values at the end of T3 administration. The activity of citrate synthase and the capacity to oxidize pyruvate plus malate decreased rapidly after discontinuing T3 administration, reaching values below those of base line controls in 14 days, but were not different than controls at 21 days. The activity of cytochrome c oxidase decreased more slowly, reaching base line values 28 days after discontinuing treatment with T3. Fiber composition was studied in cross-sections treated to demonstrate ATPase activity after acid pre-incubation. Three fiber types were present in the soleus of control animals: Type 1 with a strong ATPase reaction (86%), type II a with a weak ATPase reaction (12%) and a small proportion of type IIc with intermediate ATPase reaction (2%). After 28 days of T3 administration the proportion of type I fibers was significantly reduced (74%) while that of IIc was higher (18%). Fiber composition returned to normal between 21 and 28 days after T3 treatment was discontinued. Muscle capillarity was increased by T3 administration. Values of capillary density or capillary to fiber ratio at a given fiber cross sectional area were approximately 30% higher than controls at the end of T3 treatment and remained high until 21 days after discontinuing T3.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Changes in soleus muscle capillarity, oxidative capacity and fiber composition in rats recovering from hyperthyroidism. 401 1

Modifications of enzyme activities (creatine kinase and its B subunit; adenylate kinase; hexokinase; phosphofructokinase; lactate dehydrogenase; malate dehydrogenase, isocitrate dehydrogenase; citrate synthase; acetylcarnitine transferase; beta-hydroxyacetyl-CoA dehydrogenase; cytochrome c oxidase) in gastrocnemius muscle and myocardium were reported after two forms of training with or without administration of anabolic steroid. Endurance training was on a horizontal motor-driven treadmill, 2 km X hr-1, 5 days a week for 0.5 hr per day for 5 weeks. In the case of power endurance training there was a slope of 45 degrees. Enzyme activities in controls and treated guinea pigs, as well as treatment-induced enzyme activity changes are time dependent. Some of these activities correlate linearly with one another; such correlations characterize the effect of adaptation. Endurance training and power endurance training in this study induce similar modifications and seem to differ essentially in the daily work load. The anabolic steroid methandrostenolone (dianabol) induces modifications which training does not bring about but which training at least partially eliminates.
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PMID:Effects of training and methandrostenolone (an anabolic steroid) on energy metabolism in the guinea pig: changes in enzyme activities in gastrocnemius muscle and myocardium. 407 21

Sixteen male subjects (20-31 yr) trained for 8 wk on cycle ergometers. Eight of the subjects were treated during the training period with the beta-adrenoceptor blocker propranolol (160 mg/day). During all pre-and posttraining tests, subjects were uninfluenced by the medication. Training-induced increases in VO2max and decreases in blood lactate and norepinephrine concentrations at submaximal exercise were not different between the beta-blockade and the placebo groups. The activities of the mitochondrial enzymes citrate synthase (CS), succinate dehydrogenase (SDH), cytochrome c oxidase (Cyt-c-ox), and 3-hydroxyacyl-CoA dehydrogenase (HAD) in the quadriceps femoris muscle increased significantly (P less than 0.01) with training (beta-blockade group, +47, +33, +38, and 22%; placebo group, +75, 70, +87, and +63%, respectively). Cyt-c-ox and HAD increased significantly more in the placebo group than in the beta-blockade group, while a tendency to an increase was noted for SDH. Muscle capillary density increased similarly (+17-19%) with training in the two groups (P less than 0.01). In conclusion, subjects training under the influence of a therapeutic level of beta-adrenergic blockade show marked increases in both the respiratory capacity and the capillary supply of the engaged skeletal muscles. However, the increase in muscle mitochondrial enzymes may be less apparent than in the normal state.
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PMID:Beta-adrenergic blockade and training in human subjects: effects on muscle metabolic capacity. 608 81

The activities of several lysosomal enzymes were assayed in control and in exercise-hypertrophied cardiac muscle of mice (Mus musculus). The repeated running program increased the activity of beta-glucuronidase (16.1%) in mouse cardiac muscle. Decreased activities of beta-N-acetylglucosaminidase (10.8%), acid ribonuclease (10.7%), and arylsulphatase (14.2%) were observed in the hypertrophied myocardium. The activities of acid deoxyribonuclease, cathepsin C, cathepsin D, and p-nitrophenylphosphatase as well as the activities of citrate synthase and cytochrome c oxidase, mitochondrial enzymes, were unaffected in cardiac muscle. We suggest that lysosomal enzyme responses are selective and highly different in physiologically and pathologically induced cardiac hypertrophies.
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PMID:Changes in lysosomal enzyme activities in exercise-induced cardiac hypertrophy of mice. 622 47

We studied the effects of running-training, heavy exercise and termination of training on the heart weight, the ratio heart to body weight and the cardiac muscle activities of actomyosin ATPase, citrate synthase, succinate dehydrogenase, cytochrome c oxidase, malate dehydrogenase, adenylate kinase and beta-glucuronidase with adult male NMRI-mice. Stable hypertrophy (6-7%), estimated by the ratio heart or ventricle weight to body weight, was achieved by 28 exercises and it was dependent on the running speed (20 vs. 25 m X min-1). The withdrawal of training for 5-61 days did not permanently decrease the heart weight or the heart to body weight ratio to the level of sedentary controls. The activity of enzymes of energy metabolism or actomyosin ATPase were not affected by training, heavy exercise or terminated training. beta-glucuronidase activity slightly (20-25%) increased in the trained animals and remained at a higher level during the period of terminated training. The results suggest that the capacity for aerobic metabolism of normal mice heart is sufficient to meet the enhanced demand for ATP imposed by running-training and that the heart enlargement occurs in equal proportions with the enzymatic potential of the cardiac tissue.
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PMID:Selected enzyme activities in mouse cardiac muscle during training and terminated training. 623 64

1. The palmitate oxidation rate was measured in intact diaphragm and m. flexor digitorum brevis and in whole homogenates of heart, diaphragm and m. quadriceps of developing rats between late foetal life and maturity. Activities of the mitochondrial enzymes cytochrome c oxidase and citrate synthase were also determined. 2. Immediately after birth the palmitate oxidation rate increases markedly in both intact diaphragm and m. flexor digitorum brevis and falls gradually after day 1 to adult values which are about 35% of those at birth. 3. The oxidation capacities of diaphragm and m. quadriceps, but especially of heart, increase steadily during development, starting before birth and reaching adult values at 15-20 days postnatally. The activities of the mitochondrial enzymes show a similar developmental pattern. 4. In heart the increase of oxidative capacity is the result of an increase of both mitochondrial content and mitochondrial activity. The mitochondrial contents of diaphragm and m. quadriceps, on the other hand, decrease with age and the increase of their oxidative capacities is due to a large rise of the mitochondrial activity.
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PMID:Postnatal development of palmitate oxidation and mitochondrial enzyme activities in rat cardiac and skeletal muscle. 628 42

The effect of endurance training on skeletal muscle myoglobin concentration in man was investigated. 8 healthy sedentary males (20-31 yrs) trained on cycle ergometers 40 min/day, 4 days a week for 8 weeks. The work consisted of continuous exercise at a work load that during the last 5 weeks corresponded to 75% of the pretraining maximal oxygen uptake (VO2 max). The training program resulted in a 7% increase in VO2 max (p less than 0.01). The activities of the mitochondrial enzymes citrate synthase (CS), succinate dehydrogenase (SDH) and cytochrome c oxidase (Cyt-c-ox) in the quadriceps femoris muscle, as indicators of muscle respiratory capacity, increased by 62-82% (p less than 0.01). The metabolic adaptation of skeletal muscle was further indicated by a 17% increase in the work load corresponding to a blood lactate concentration of 4 mmol/l, as determined by a progressive exercise test (p less than 0.05). There was, however, no change in the myoglobin concentration of the thigh muscle with training (-1%, NS). It is suggested that endurance exercise in man at 75% of the maximal oxygen uptake does not severely tax the functions of myoglobin in skeletal muscle.
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PMID:Dissociation of training effects on skeletal muscle mitochondrial enzymes and myoglobin in man. 630 98

Concentric left ventricular hypertrophy was produced in puppies by coarctation banding of the aorta at age 7 weeks. Hemodynamic, morphologic and biochemical studies were carried out 18 months after the operation. Systolic blood pressure proximal to the aortic constriction was 216 +/- 16 mmHg in experimental dogs compared with 115 +/- 5 mmHg in littermate control dogs. Ejection fraction of control and experimental dogs were 59 +/- 4 and 64 +/- 7, respectively. The left ventricular end-diastolic pressure was 6.0 +/- 0.4 in control and 8.4 +/- 1.1 in experimental dogs. There was no sign of overt heart failure in the experimental dogs. Anatomical analysis of different regions of the heart indicated that LV mass in the experimental dogs was increased by about 60%. Ultrastructure of mitochondria in situ, as observed under electron microscope, was normal both in control and hypertrophic hearts. Mitochondria isolated from epicardial and endocardial regions of the stable hypertrophic hearts showed normal rates of respiration, phosphorylation, citrate synthase, and cytochrome c oxidase activities compared to those isolated from hearts of littermate control dogs. It was, therefore, concluded that mitochondrial function is adequately preserved to meet the increased demand for energy in this model of stable cardiac hypertrophy of long duration.
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PMID:Mitochondrial function in canine experimental cardiac hypertrophy. 630 71


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