Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:1.1.1.27 (lactate dehydrogenase)
 29,211 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

This study compared the skeletal muscle metabolic adaptations in response to combined eccentric and concentric or concentric resistance training regimens. Twenty-six physically active males were assigned to either the combined eccentric and concentric group (n = 10), the concentric group (n = 10) or the control group (n = 6). The combined eccentric and concentric and the concentric groups performed four to five sets of maximal, voluntary bilateral quadriceps muscle actions at 1.05 rad s-1 using a speed-controlled dynamometer three times per week for 12 weeks. The concentric group performed 12 concentric actions per set, whereas the combined eccentric and concentric group performed six coupled eccentric and concentric actions per set. Bilateral percutaneous muscle biopsies were obtained from m. vastus lateralis at rest pre- and post-training. Tissue samples were analysed for contents of adenosine triphosphate, creatine phosphate and creatine and for enzyme activities of citrate synthase, lactate dehydrogenase, myokinase, phosphofructokinase, hexokinase and Mg2(+)-ATPase using fluorometric techniques. Histochemical staining procedures were employed to determine capillary supply. The overall increase (P less than 0.05) in muscle strength was greater (P less than 0.05) for the combined eccentric and concentric group than for the concentric group. Enzyme or substrate contents and capillary supply were unaltered after either type of training. It is suggested that substantial increases in muscle strength may occur in response to resistance training without enhancing or compromising metabolic function of skeletal muscle.
 ...
PMID:Effects of eccentric and concentric resistance training on skeletal muscle substrates, enzyme activities and capillary supply. 208 17

Several intracellular enzymes have been shown to have altered total activity or isoenzyme composition in cardiac hypertrophy. This study tests the hypothesis that the accumulation of the fetal-type (BB + MB) creatine kinase (CK) isoenzymes in hypertrophied adult myocardium is related to an increase in blood pressure. Consideration was made for the location, size, and hemodynamic load of the myocytes. By using the two-kidney, one-clip (2K1C) rat model of renal hypertension with and without hydralazine treatment, CK (total and isoenzyme), lactate dehydrogenase, and citrate synthase activities and myocyte size were measured. An increased heart weight/body weight ratio occurred in both untreated 2K1C rats (4.15 +/- 0.09) and hydralazine-treated 2K1C rats (4.12 +/- 0.13) as compared with control rats (3.25 +/- 0.10). Blood pressure was high only in untreated 2K1C rats (196 +/- 9 mm Hg), as compared with hydralazine-treated 2K1C rats (142 +/- 6 mm Hg) and control rats (135 +/- 3 mm Hg). Myocytes were isolated from five ventricular regions: left ventricular epicardial and endocardial free wall, left and right halves of the interventricular septum, and right ventricular free wall. Regional differences in normal and hypertrophied myocardium were demonstrated for morphological and biochemical parameters, with the greatest changes occurring in left ventricular endocardium. The shift in CK isoenzyme expression toward accumulating more BB + MB was greater in "hypertensive hypertrophy" (untreated 2K1C rats) than in "nonhypertensive hypertrophy" (hydralazine-treated 2K1C rats). Calculations incorporating isolated myocyte volume showed that the cellular content of total CK remained the same during the hypertrophic process, accounting for a decrease in the tissue activity. Measurement of lactate dehydrogenase and citrate synthase activities suggests that hypertrophied myocardium has relatively higher glycolytic capacity and that this effect is exacerbated in the presence of high blood pressure. We conclude that increased blood pressure is more closely linked to the fetal CK isoenzyme shift than is hypertrophy alone.
 ...
PMID:Regional changes in creatine kinase and myocyte size in hypertensive and nonhypertensive cardiac hypertrophy. 214 29

Tissue samples from the right atrium and ventricle of the same heart were obtained during surgery on 45 children operated on for congenital heart disease (tetralogy of Fallot, ventricular septal defect). Significant enzyme activity differences were found between atrial and ventricular muscle. Aerobic metabolism enzymes (citrate synthase, malate dehydrogenase), with lactate metabolism (lactate dehydrogenase) and fatty acid oxidation (hydroxyacyl-SoA dehydrogenase) showed significantly higher activities in ventricular muscle tissue. In contrast, hexokinase, the enzyme responsible for glucose phosphorylation was significantly higher in the atria. Hence, the right ventricle can utilize and oxidize to the full all the main nutrients (fatty acids, glucose and lactate) while the right atrium utilizes primarily glucose. These atrio-ventricular differences are independent of the type of congenital heart disease and their existence can be presumed in healthy persons, too.
 ...
PMID:Different activities of energy metabolism enzymes in children's cardiac atria and ventricles. 224 58

The metabolic pathways by which the glycogen is utilized by fetal tissues is not well established. In the present study the ontogeny of seven key enzymes involved in glycolysis and the tricarboxylic acid cycle has been established for rabbit fetal lung, heart, and liver. In the fetal lung the activities of phosphofructokinase, pyruvate kinase, lactic dehydrogenase, citrate synthase, and malate dehydrogenase increase from day 21 to 25. Thereafter the levels either drop to day 19 levels or do not change. The isocitrate dehydrogenase activity continues to increase from day 19 of gestation to maximum level on day 31 of gestation. In fetal heart the pattern of activity is similar, but in fetal liver most of the enzymes reach maximum levels earlier and, with the exception of pyruvate kinase, do not show a significant fall in activity near term. The pattern of development of pyruvate dehydrogenase complex is different; maximum activity is observed on day 27 in fetal lung and heart and on day 21 in fetal liver. These results indicate that all three fetal tissues can oxidize glucose. Also, the accumulation of glycogen, particularly in fetal lung, appears to ensure that at specific times during gestation adequate quantities of energy (ATP) and substrates, required for surfactant phospholipid synthesis, are available independent of maternal supply of glucose or during brief episodes of hypoxia.
 ...
PMID:Ontogeny of pyruvate dehydrogenase complex and key enzymes involved in glycolysis and tricarboxylic acid cycle in rabbit fetal lung, heart, and liver. 226 16

Nine bodybuilders performed heavy-resistance exercise activating the quadriceps femoris muscle. Intermittent 30-s exhaustive exercise bouts comprising 6-12 repetitions were interspersed with 60-s periods for 30 min. Venous blood samples were taken repeatedly during and after exercise for analyses of plasma free fatty acid (FFA) and glycerol concentration. Muscle biopsies were obtained from the vastus lateralis muscle before and after exercise and assayed for glycogen, glycerol-3-phosphate, lactate and triglyceride (TG) content. The activities of citrate synthase (CS), lactate dehydrogenase, hexokinase (HK), myokinase, creatine kinase and 3-hydroxyacyl-CoA dehydrogenase (HAD), were analysed. Histochemical staining procedures were used to assess fibre type composition, fibre area and capillary density. TG content before and after exercise averaged (SD) 23.9 (13.3) and 16.7 (6.4) mmol kg-1 dry wt. The basal triglyceride content varied sixfold among individuals and the higher the levels the greater was the change during exercise. The glycogen content decreased (P less than 0.001) from 690 (82) to 495 (95) mmol kg-1 dry wt. and lactate and glycerol-3-phosphate increased (P less than 0.001) to 79.5 (5.5) and 14.5 (7.3) mmol kg-1 dry wt., respectively, after exercise. The HK and HAD/CS content respectively correlated with glycogen or TG content at rest and with changes in these metabolites during exercise. FFA and glycerol concentrations increased slightly (P less than 0.001) during exercise. Lipolysis may, therefore, provide energy during heavy-resistance exercise of relatively short duration. Also, storage and utilization of intramuscular substrates appear to be influenced by the metabolic profile of muscle.
 ...
PMID:Glycogen and triglyceride utilization in relation to muscle metabolic characteristics in men performing heavy-resistance exercise. 228 98

The histochemical, biochemical, and electrophysiological properties of selected muscles were evaluated in spontaneously hypertensive rats (SHR) and compared with their normotensive Wistar-Kyoto (WKY) counterparts. As early as 4 wk of age, slow muscles (soleus) of SHR displayed a significant alteration in fiber type distribution with a decrease of slow-twitch fibers (from 64 to 53%) and a simultaneous increase of type IIA-fibers (from 19 to 39%). In addition, soleus from young SHR had a significant enhancement of both oxidative (citrate synthase, 3-hydroxyacyl-CoA dehydrogenase) and glycolytic [lactate dehydrogenase (LDH)] capacities, which could be partly related to a capillary rarefaction. During development (from the 4th to the 12-14th wk), in the soleus muscle the histochemical differences between SHR and WKY were amplified, whereas most of the enzymatic differences between strains were abolished, except for a significantly higher LDH activity. These histochemical changes had only marginal repercussions on soleus electrophysiological properties. SHR animals had a significantly higher basal metabolic rate, which could not be accounted for by elevation of thyroid hormones. The origin of the slow-to-fast fiber type transition in slow muscle remains unclear but could be related to the increased level of plasma catecholamines in SHR. Indeed, chronic treatment of rats with a beta 2-receptor agonist has been reported to cause slow-to-fast muscle fiber transition [R. J. Zeman, R. Ludemann, T. G. Easton, and J. D. Etlinger. Am. J. Physiol. 254 (Endocrinol. Metab. 17): E726-E732, 1988].
 ...
PMID:Evidence of a slow-to-fast fiber type transition in skeletal muscle from spontaneously hypertensive rats. 230 28

1. The activities of hexokinase, lactate dehydrogenase and citrate synthase were maintained in mesenteric lymph node lymphocytes during 4 hr of culture: the activity of glutaminase increased during this period of time. 2. In splenocytes, the activity of hexokinase decreased markedly during the 4 hr period, whereas those of lactate dehydrogenase and glutaminase remained constant, and that of citrate synthase increased dramatically. 3. In both mesenteric lymphocytes and splenocytes, addition of the T-cell mitogens, phytohaemagglutinin or concanavalin-A, to the culture medium caused decreases in the activities of both hexokinase and citrate synthase. 4. In contrast, these mitogens increased the activity of glutaminase in both cell types. 5. Addition of the B-cell mitogen, bacterial lipopolysaccharide, had little effect on hexokinase, lactate dehydrogenase or citrate synthase but increased markedly that of glutaminase in mesenteric lymph node lymphocytes. 6. In splenocytes this mitogen prevented much of the decrease in hexokinase activity, increased the activities of citrate synthase and glutaminase but had little effect on that of lactate dehydrogenase.
 ...
PMID:Effect of mitogens on the maximum activities of hexokinase, lactate dehydrogenase, citrate synthase and glutaminase in rat mesenteric lymph node lymphocytes and splenocytes during the early period of culture. 233 97

The purpose of this study was to investigate metabolic changes in equine muscle from birth to 1 yr of age. Duplicate biopsies from the middle portion of the gluteus medius were obtained from a depth of 2 cm beneath the superficial fascia at 1 day, 7 days, 1 mo, 3 mo, 6 mo, and 1 yr of age in 11 quarter horses and at 1 day, 3 mo, 6 mo, and 1 yr of age in 5 Standardbreds. Muscle enzyme activities determined were citrate synthase, 3-hydroxyacyl-CoA dehydrogenase, phosphorylase, and lactate dehydrogenase. Percent fast-twitch, fast-twitch high oxidative, and slow-twitch oxidative fiber types were determined using succinate dehydrogenase and myosin adenosinetriphosphatase (pH 9.4) histochemical stains. Histochemically determined muscle fiber-type percents did not change dramatically with increasing age. However, lactate dehydrogenase activity increased threefold in quarter horses and twofold in Standardbreds, and phosphorylase activity increased sixfold in quarter horses and sevenfold in Standardbreds from 1 day to 6 mo of age. Citrate synthase and 3-hydroxyacyl-CoA dehydrogenase activities decreased during the first 3 mo of age in quarter horses.
 ...
PMID:Changes in the metabolic profile of equine muscle from birth through 1 yr of age. 234 82

The aim of this study was to investigate the effects of neural activity on the expression of fibre-type-specific patterns of metabolic enzymes at the levels of transcription and translation. For this purpose, changes in tissue amounts of citrate synthase (CS) and the H- and M-subunits of lactate dehydrogenase (LDH) were followed in fast-twitch rabbit muscles during low-frequency (10 Hz, 12 h/day) nerve stimulation. These stimulation-induced alterations were correlated with changes in tissue amounts of the total poly(A)+ (polyadenylated) RNA, poly(A)+ RNAs specifically translatable in vitro, yield of total ribosomes and distributions of monosomes and polysomes. The tissue contents of poly(A)+ RNAs translatable in vitro coding for CS and H- and M-LDH were quantified by immunoprecipitation of their translation products. Increases in total ribosome yields occurred after 4 days' stimulation, reaching a maximum between 14 and 21 days. Stimulation for only 1-2 days greatly increased the amount of monosomes. An increase in polysomes occurred before that in total ribosomes, suggesting that monosomes were integrated into polysomes. Total poly(A)+ RNA significantly increased in muscles stimulated for more than 6 days. A maximum increase of 2.5-fold was attained after 14-21 days. Chronic stimulation progressively induced the appearance of LDH isoenzymes containing the H-subunit, with a predominance of LDH-3. This shift corresponded to a slow decay of the M-subunit and a 2-fold steep increase in the H-subunit. These changes correlated with those of the respective poly(A)+ RNAs translatable in vitro, thus indicating that the re-arrangement of the LDH isoenzyme pattern is mainly due to qualitatively and quantitatively altered transcription. The increase in CS was biphasic and consisted of a moderate rise during the first 4 days of stimulation and a steep rise thereafter. The latter coincided with a steep increase in poly(A)+ RNA translatable in vitro coding for CS. In view of the early increase in translational capacity, it was concluded that the initial rise in CS resulted from selective post-transcriptional control and enhanced translation in vivo of existing mRNA, whereas its steep increase was due to enhanced transcription. These results indicate that the neurally regulated expression of phenotype-specific properties in muscle includes control of both transcription and translation.
 ...
PMID:Neural control of gene expression in skeletal muscle. Effects of chronic stimulation on lactate dehydrogenase isoenzymes and citrate synthase. 243 87

Metabolic adaptations were studied in papillary muscle from 18 patients undergoing open-heart surgery for mitral valve disease. Analyses were made of myoglobin (MG), the enzymes lactate dehydrogenase (LD) with its isoenzymes, glyceraldehyde phosphate dehydrogenase (GAPDH), phosphofructokinase (PFK), citrate synthase (CS) and creatine kinase (CK) with its isoenzymes MB (CK-MB) and mitochondrial CK (CK-MIT). Myocardial function was assessed with left ventricular angiography. Positive and significant correlations were found between enzymes of oxidative metabolism, i.e. CS on the one hand and MG (r = 0.76), LD1 (r = 0.68), CK-MIT (r = 0.86) and CK-MB (r = 0.65) on the other. Indicators of glycolysis--PFK, GAPDH and LD3--varied independently of CS. LD3% was directly related to GAPDH (r = 0.66). In a sub-group of 12 patients with isolated mitral regurgitation due to myxomatous valve degeneration, LD3% rose (r = 0.72) with increasing myocardial derangement which, however, showed no relationship with any other marker. Thus the capacities of oxidative and glycolytic pathways did not co-vary. Volume load appeared not to affect oxidative capacity, while the anaerobic fraction of glycolysis was increased.
 ...
PMID:Key enzymes of myocardial energy metabolism in papillary muscle of patients with mitral valve disease--relation to left ventricular function. 252 75


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>