Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:1.1.1.27 (lactate dehydrogenase)
29,211 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Selected biochemical parameters of the ventricular myocardium were compared among several orders of adult mammals with established differences in resting heart rate (cattle, 51 beats/min; swine, 68; canine, 107; rabbit, 256; guinea-pig, 273; rat, 355; mouse, 475). It was hypothesized that the biochemical character of mammalian myocardia is associated with the chronic functional demand on the muscle. Therefore, differences observed in the myocardial biochemical potential among the species could reflect differences in resting heart rate. Myocardia from smaller mammals with higher resting heart rate had significantly (P less than 0.05) higher maximal activities of citrate synthase, 3-hydroxyacyl-CoA dehydrogenase, lactate dehydrogenase (muscle/total), hexokinase and oxidation rates of glucose and palmitate than did larger mammals with lower resting heart rate. Maximal activities of phosphorylase and phosphofructokinase were more uniform across the animals. Correlation coefficients determined among average values of measured biochemical parameters and resting heart rate indicated that resting heart rate was closely associated with: citrate synthase (r = 0.86), 3-hydroxyacyl-CoA dehydrogenase (r = 0.93), ratio muscle/total lactate dehydrogenase (r = 0.89), hexokinase (r = 0.89), glucose oxidation (r = 0.88), and palmitate oxidation (r = 0.93). Significant correlations were observed among all of these parameters with the exception of citrate synthase vs. 3-hydroxyacyl-CoA dehydrogenase, and glucose oxidation vs. muscle/total lactate dehydrogenase. It was concluded that the oxidative capacity of mammalian myocardia was closely associated with resting heart rate, whereas the glycolytic potential of the myocardia was more uniform among the species.
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PMID:Biochemical characteristics of mammalian myocardia. 274 58

Percutaneous needle biopsy samples were obtained from the vastus lateralis and soleus muscles before and after 30 d of 6 degree head-down bedrest to determine the influence of this model of simulated microgravity on human skeletal muscle. Fiber atrophy was evident in both muscles with both fast-twitch and slow-twitch fiber cross-sectional areas decreasing. Predominant atrophy of slow-twitch fibers was not evident. The soleus had a greater proportion of slow-twitch fibers than the vastus lateralis before bedrest. Neither muscle showed a change in fiber type percentage with bedrest. Phosphofructokinase and lactate dehydrogenase activities in the soleus and vastus lateralis muscles were similar before and after bedrest. The activities of beta-hydroxyacyl-CoA dehydrogenase and citrate synthase, however, were reduced during bedrest with these responses being somewhat greater in the soleus. While the ultrastructure of most of the fibers of the soleus and vastus lateralis appeared normal after bedrest, evidence of remodeling was present in both muscles. The proliferation of core/targetoid lesions, honeycomb networks, regenerating satellite cells, necrotic foci and myofibrillar disorganization after bedrest indicates that force development is an important factor in determining the organization of the fine structure of muscle. The results indicate that short-duration exposure to simulated microgravity decreases fiber size and the capacity for aerobic energy supply of human skeletal muscle. Moreover, disorganization of the contractile machinery occurs. Thus, it appears that bedrest alters the "normal" load-time constraints imposed on skeletal muscle sufficiently to change its inherent structural and metabolic characteristics.
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PMID:Structural and metabolic characteristics of human skeletal muscle following 30 days of simulated microgravity. 276 50

Administration of clofibrate for 21 days to rats increased the malic enzyme activity in the kidney cortex by about 80 per cent. This effect seems to be specific since the drug did not alter significantly the activity either of lactate dehydrogenase, citrate synthase or total mitochondrial protein content in this organ. The increase in activity of malic enzyme in the 13,000 g supernatant (extramitochondrial) fraction in rats treated with the drug was about 80 per cent, whereas in the pellet (mitochondrial fraction) it was about 40 per cent. The specific activity of malic enzyme in the kidney cortex cytosol from clofibrate-treated rats was about twice that in controls. In contrast clofibrate treatment did not affect its specific activity in isolated mitochondria. Calculations showed that 0.57 and 0.53 mumoles min-1 g-1 wet tissue of mitochondrial malic enzyme was obtained in control and clofibrate-treated rats respectively. Thus, clofibrate feeding increases the amount of cytoplasmic but not mitochondrial malic enzyme activity.
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PMID:Clofibrate feeding increases cytoplasmic but not mitochondrial malic enzyme activity in rat kidney cortex. 276 73

The quadriceps muscles from 20- 30- and 70-year-old clinically healthy men and women were studied regarding maximal isometric and isokinetic muscle torque in Newton metres (Nm), morphology and enzyme activity. Biopsy specimens were taken from the vastus lateralis muscle and freeze-dried, and individual fibres were dissected out and identified as type I or type II. The activities of citrate synthase (CS), 3-OHacyl-coA dehydrogenase (HAD), lactate dehydrogenase (LDH), myokinase (MK) and creatine phosphokinase (CPK) were determined in pools of type I and type II fibres. In both age groups a higher oxidative (CS, HAD, 1.3-1.5 x) and a lower glycolytic (LDH, 0.7 x) capacity was found in type I than in type II fibres. The myokinase activity was higher in type II (2 x) than in type I, whereas CPK activity was similar. The young men showed higher CS activity in both type I and type II fibres (1.5 x) and higher CPK activity in type I fibres (1.4 x) than the young women. There were only minor changes in oxidative or glycolytic capacities in relation to age. Myokinase was the only enzyme that decreased markedly with age in both pools of fibre types. Type II fibre area and mean fibre area correlated significantly to muscle torque in both sexes. In men, myokinase activity in type II fibres was significantly correlated to type II fibre area and to maximal muscle torque.
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PMID:Enzyme activities in type I and II muscle fibres of human skeletal muscle in relation to age and torque development. 277 60

This paper describes an organ culture system that maintains frog sartorius muscles in good condition for 5 days. In the absence of serum and insulin, muscles maintained at approximately 93% of resting length atrophied with significant decreases in dry weight, protein content, and contractile force, and in the levels of activity of citrate synthase, lactate dehydrogenase, and creatine kinase. Inclusion of 1.0 mU/ml of insulin in the culture medium prevented the decreases in muscle mass, twitch tension, and citrate synthase activity and minimized the decreases in lactate dehydrogenase, creatine kinase, and tetanic tension. Inclusion of 10% serum, in addition to 1 mU/ml insulin, in the medium did not have clear cut additional benefits. Stretching muscles to 110% of resting length (L0) resulted in marked deterioration with decreases in total protein, enzyme levels, and contractile force. Keeping muscles at approximately 93% L0 was as effective as maintenance at L0 in preventing atrophy and loss of contractile force and enzyme activities. This organ culture procedure, which maintains frog sartorius muscle in good condition without serum for at least 5 days, may provide a useful model for studying the regulatory mechanisms responsible for a variety of adaptations in muscle.
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PMID:Organ culture of frog muscle: maintenance of mass, enzyme levels, and contractile force. 278 58

Five Standardbred trotters were trained on a treadmill 3 times/wk for 12 wk by intervals of draft-loaded exercise. The draft load was 34 kp and the velocity approximately 7 m/s. Muscle biopsies were taken from the gluteus medius and longissimus muscles before training and after 2, 4, 8, and 12 wk of training and from the brachiocephalicus muscle before and after training. Both the percentage and the area of type IIa fibers increased and the percentage of type IIb fibers decreased in the gluteus medius muscle during the first 2 wk of training, and then no further significant difference was noted. The percentage of type I fibers increased in the brachiocephalicus muscle, and the area of type IIb fibers increased in the longissimus muscle. The citrate synthase activity increased in the gluteus muscle only, and the increase was seen during the first 2 wk. No significant differences were seen in 3-hydroxy-acyl-CoA dehydrogenase and lactate dehydrogenase activities in the muscles during the entire training period. Less glycogen was utilized in the gluteus muscle and less blood lactate accumulated when the horses performed an unloaded submaximal exercise test after compared with before training. It can be concluded that rapid changes are induced in the gluteus medius muscle when horses are trained pulling a light-draft resistance at a submaximal trotting speed.
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PMID:Effects of a draft-loaded interval-training program on skeletal muscle in the horse. 279 58

Tissue specimens from the right atrium and ventricle of the same heart were obtained during surgery in 45 children operated on account of congenital heart disease (tetralogy of Fallot and ventricular septal defect). Significant differences were found in the enzyme activities between the atrial and ventricular musculature. The activities of enzymes associated with aerobic metabolism (citrate synthase, malate dehydrogenase, with lactate metabolism) lactate dehydrogenase (and the fatty acid oxidation) hydroxyacyl-SoA-dehydrogenase) were significantly higher in the ventricular musculature. Hexokinase, the enzyme responsible for glucose phosphorylation was on the other hand, significantly higher in the atria. From this ensues that the right ventricle can utilize and oxidize to a full extent all main nutrients (fatty acids, glucose and lactate), while the right atrium utilizes above all glucose. These atrio-ventricular differences do not depend on the type of the congenital heart disease and it may be assumed that they exist also in healthy subjects.
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PMID:[Differences in the activity of enzymes associated with energy metabolism in the heart atria and ventricles in children]. 280 28

Patients with heart failure frequently exhibit abnormal skeletal muscle metabolic responses to exercise, as assessed with 31P NMR. To investigate whether these metabolic abnormalities are due to intrinsic skeletal muscle changes, we performed gastrocnemius muscle biopsies on 22 patients with heart failure (peak VO2, 15.4 +/- 4.7 ml/kg/min; ejection fraction, 20 +/- 7%) and on eight normal subjects. Biopsies were analyzed for fiber type and area, capillarity, citrate synthase, phosphofructokinase, lactate dehydrogenase, and beta-hydroxyacyl CoA dehydrogenase activity. All patients with heart failure also underwent 31P NMR studies of their calf muscle during plantarflexion at three workloads. Muscle pH responses and the relation of the ratio of inorganic phosphate to phosphocreatine (Pi/PCr) to systemic VO2 were then evaluated. Compared with normal subjects, patients with heart failure exhibited a shift in fiber distribution with increased percentage of the fast twitch, glycolytic, easily fatigable type IIb fibers (normal subjects, 22.7 +/- 10.1; heart failure, 33.1 +/- 11.1%; p less than 0.05), atrophy of type IIa (normal subjects, 5,477 +/- 1,109; heart failure, 4,239 +/- 1,247 microns 2; p less than 0.05) and type IIb fibers (normal subjects, 5,957 +/- 1,388; heart failure, 4,144 +/- 945 microns 2; p less than 0.01), and decreased activity of beta-hydroxyacyl CoA dehydrogenase (normal subjects, 5.17 +/- 1.44; heart failure, 3.67 +/- 1.68 mol/kg protein/hr; p less than 0.05). No significant linear correlation could be identified between the slope of the Pi/PCr to VO2 relation and muscle histochemistry or enzyme activities. Similarly, no linear relation was found between intracellular pH at peak exercise and any muscle variable.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Contribution of intrinsic skeletal muscle changes to 31P NMR skeletal muscle metabolic abnormalities in patients with chronic heart failure. 280 70

Six acidic glycosidase activities in cultured human retinal pigment epithelium (RPE) cells from donors of different ages (19 to 80 years) were studied with regard to pH optimum, Km, Vmax and specific activity. For alpha-mannosidase we found significant age-dependent decreases in specific activity and Vmax but not in Km. The other glycosidases and acid phosphatase, lactate dehydrogenase (LDH) and citrate synthase showed no change in these parameters with donor age. The alpha mannosidase activity of older donor cells could be activated almost 2-fold by the addition of zinc. This is the first report of age-dependent change in a human RPE lysosomal enzyme. Since alpha-mannosidase is probably required for the degradation of rhodopsin in the phagolysosomal system of the RPE, decrease in this enzyme activity may lead to accumulation of undigested rod outer segments (ROS) and drusen, both of which are associated with age-related macular degeneration (AMD).
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PMID:A donor-age-dependent change in the activity of alpha-mannosidase in human cultured RPE cells. 280 91

Nonsynaptic mitochondria isolated from rat brain hippocampus were compared with those obtained by means of the same preparative procedure from cerebral cortex and striatum. Protein recovery, marker enzyme activities (lactate dehydrogenase, citrate synthase, and acid phosphatase), state 4 respiration, and response to hypoosmotic shock showed no difference among the three cerebral regions, suggesting homogeneous behavior during the subfractionation procedure. Cholinergic markers--choline acetyltransferase, acetylcholinesterase activities, and high-affinity choline uptake--evaluated on synaptosomes showed the classic regional pattern with an enrichment in the striatum (striatum much greater than hippocampus). The coupling state of the mitochondrial fractions was maintained (respiratory control ratios ranging from 3.62 to 5.08 with glutamate + malate as oxidizable substrates), showing a metabolic competence sufficient to perform metabolic studies. Regional differences were found in state 3, uncoupled state of respiration, and cytochrome oxidase activity. Hippocampus showed the lower values (hippocampus less than striatum less than cortex). A possible role of this lower capacity of mitochondrial energy metabolism in determining the sensitivity of hippocampal neurons to ischemia or epileptic seizures is suggested.
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PMID:Oxidative metabolism of nonsynaptic mitochondria isolated from rat brain hippocampus: a comparative regional study. 283 1


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