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At least 19 recordsLinked to original sources
PubMed1979

Fiber composition, fiber size and enzyme activities in vastus lateralis of elite athletes involved in high intensity exercise.

In order to determine the influence of an extensive history of participation in high intensity activity on muscle fiber type, fiber size, and metabolic profile, elite ice hockey players were selected for investigation from three different leagues. Biopsy samples from the vastus lateralis muscle were obtained from different groups of players prior to and following the season and compared with control subjects. No significant differences were found in the percentage (49.6 vs. 43.8%) or the size of the ST fibers between the elite athletes and the control group, nor was there any significant alteration following the season of play in these variables. For the FT fiber subgroups, a reduction in the FTb (12.2 vs. 3.9%) and an increase in FTa (38.0 to 45.2%) fiber populations occurred over the season. Similarly, increases in fiber area were observed for both FT subgroups pre to post season. Of the enzymes studied only 3-hydroxyacyl CoA dehydrogenase was elevated in the post season measures, while total phosphorylase and phosphofructokinase were significantly lower. The metabolic pattern exhibited does not appear to be substantially different from what would be expected from an untrained group of similar fiber distribution.

Adolescent↗
PubMed1979

The effect of training and detraining on several enzymes in horse skeletal muscle.

Training and detraining had little effect on the activity of glycogen synthase, hexokinase, glycerol 3-phosphate dehydrogenase or total protein. The activity of 3-hydroxyacyl-CoA dehydrogenase increased markedly during training. After 5 weeks of detraining, the activity of 3-hydroxyacyl-CoA dehydrogenase was returning to pre-training values, whilst by 10-week detraining, the levels were increasing again.

3-Hydroxyacyl CoA Dehydrogenases↗
PubMed1978

Morphology and enzyme activities of the retinal capillaries in mice with the obese-hyperglycaemic syndrome (gene symbol ob).

The retinal capillary bed from 67 obese-hyperglycaemic mice and 64 lean litter mates was isolated by trypsin digestion and investigated with respect to structure and enzyme activities. There was no significant difference in the ratio between numbers of endothelial and mural cells. The capillary walls did not show any obvious structural differences and microaneurysms were not observed. The retinal vessels from the obese-hyperglycaemic mice, however, displayed significantly higher activities of the enzymes hydroxyacyl-CoA-dehydrogenase, asparate aminotransferase (ASAT) and adenylate kinase than their lean litter mates. The activities of glutathione reductase, glucose-6-phosphate dehydrogenase (G-6-PDH) and phosphofructokinase were similar in the two experimental groups. It is suggested that the present data reflect early metabolic disturbances related to diabetic retinopathy.

3-Hydroxyacyl CoA Dehydrogenases↗
PubMed1977

Muscle adaptation to extreme endurance training in man.

To evaluate the effect of extreme endurance training on muscle fibre composition and activities of oxidative enzymes in different fibre types biopsies were taken from vastus lateralis, gastrocnemius and deltoideus of elite orienteers. Comparisons were made between the (trained) leg muscles and the (relatively untrained) arm muscles, and with leg muscles of 16--18 years old boys. The orienteers had the same percentage type I fibres and vastus lateralis and gastrocnemius as in deltoideus, but higher percentage type I fibres in vastus lateralis compared with the controls. The similarity between trained and untrained muscle in the orienteers suggests that training had not caused the high percentage type I fibres which rather might be the result of selection of individuals with the best prerequisites for high oxidative capacity. However, the distribution of type II subgroups in the leg muscles of the orienteers differed from both their own deltoideus and leg muscles of the controls, the relationship IIA/IIB being altered in favour of the more oxidative IIA. The leg muscles of the orienteers also showed an increased occurrence of the normally IIC fibre. These latter findings point at the possibility of a training induced alteration in the subgroup pattern. Unlike in the controls there was no significant difference in succinate dehydrogenase activity, measured in single fibres, between type I and II fibres in gastrocnemius of the orienteers. Thus, type II fibres have the ability metabolically to adapt to high oxidative demands. This might to some extent be mediated by a conversion from IIB to IIA form.

3-Hydroxyacyl CoA Dehydrogenases↗
PubMed1978

Cellular adaptations of the ventilatory muscles to a chronic increased respiratory load.

It is not known whether cellular adaptations of the ventilatory muscles are induced by increased respiratory loads. A chronic respiratory load was produced in rats by tracheal banding. Five weeks after the imposition of this increased load, biochemical and histochemical analyses were performed on the diaphragm and intercostal muscles. The oxidative capacity, as indicated by succinate dehydrogenase (SDH) activity, increased 38% in the diaphragm. The capacity for beta-oxidation fatty acids, as indicated by 3-hydroxy-acyl-CoA dehydrogenase (HADH) activity, increased 29%. The glycolytic capacity, as indicated by phosphofructokinase (PFK) activity, did not change. Similar enzymatic adaptations were observed in the intercostal muscles. The proportion of slow-twitch muscle fibers, as indicated by the myofibrillar adenosine triphosphatase (ATPase) stain, increased in the diaphragm, but not in the intercostal muscles. Thus, these ventilatory muscles responded with an increase in their oxidative capacity, and the diaphragm reponded with an increase in the proportion of muscle fibers having the myofibriller ATPase staining characteristic of slow-twich fibers. We conclude that cellular adaptations are induced in the ventilatory muscles by chronic increased respiratory loads.

3-Hydroxyacyl CoA Dehydrogenases↗
PubMed1979

Enzymology of butyrate formation by Butyrivibrio fibrisolvens.

Butyrivibrio fibrisolvens is a major butyrate-forming species in the bovine and ovine rumen. The enzymology of butyrate formation from pyruvate was investigated in cell-free extracts of B. fibrisolvens D1. Pyruvate owas oxidized to acetylcoenzyme A (CoA) in the presence of CoA.SH and benzyl viologen or flavin nucleotides. The bacterium uses thiolase, beta-hydroxybutyryl-CoA dehydrogenase, crotonase, and crotonyl-CoA reductase to form butyryl-CoA from acetyl-CoA. Reduction of acetoacetyl-CoA to beta-hydroxybutyryl-CoA was faster with NADH than with NADPH. Crotonyl-CoA was reduced to butyryl-CoA by NADH, but not by NADPH, only in the presence of flavin nucleotides. Reduction of flavin nucleotides by NADH was much slower than the flavin-dependent reduction of crotonyl-CoA. This indicates that flavoproteins rather than free flavin participated in the reduction of crotonyl-CoA. Butyryl-CoA was converted to butyrate by phosphate butyryl transferase and butyrate kinase.

3-Hydroxyacyl CoA Dehydrogenases↗
PubMed1979

Activities of malate dehydrogenase, 3-hydroxyacyl-CoA dehydrogenase and fructose-1,6-diphosphatase with regard to metabolic subpopulations of fast- and slow-twitch fibres in rabbit muscles.

Activities of malate dehydrogenase (MDH), 3-hydroxyacyl-CoA dehydrogenase (HAD) and fructose-1,6-diphosphatase (FDPase) were determined in single fibres dissected from freeze-dried rabbit psoas and soleus muscles. Slow-twitch fibres as determined by qualitative ATPase reaction represent a rather uniform population with regard to HAD and MDH activities. In these fibres the two enzymes are in constant proportions. FDPase is found at extremely low activities in slow-twitch fibres and because of its relatively high activity in fast-twitch fibres of soleus and psoas muscle it might be used as a marker enzyme. Fast-twitch fibres in psoas muscle represent a heterogeneous population with regard to activities of MDH as well as of HAD. The two enzyme activities are not proportional in fast-twitch psoas fibres. These findings suggest the existence of metabolic subpopulations of fast-twitch fibres having a wide range of aerobic oxidative capacities and having differences in their capacity to oxidizing fatty acids.

3-Hydroxyacyl CoA Dehydrogenases↗
PubMed1978

Enzymatic studies of liver cells obtained by fine needle biopsy from mice with the obese-hyperglycemic syndrome (genesymbol ob).

In an enzymatic study of livers from obese hyperglycemic mice (obob) and their lean litter mates, microdissected freeze-dried fine needle biopsies were used. Carbohydrate, fatty acid and ketone body metabolism was examined through assays of phosphofructokinase (PFK), 3-hydroxyacyl-CoA dehydrogenase (HOADH) and D-3-hydroxybutyrate dehydrogenase (HBDH). At 2 months of age the obob-mice showed a significant increase in PFK activity as compared to their lean litter mates. No such difference was found for the activity of HOADH and HBDH. An early increase in the initial glycolysis in the livers of obob-mice might thus be one of the factors responsible for the accelerated synthesis of lipids resulting in the fatty livers of the adult obob-mice. The present results corroborate previous studies indicating no major derangement in the fatty acid and ketone body metabolism in the livers of obob-mice. In a methodological evaluation of the technique for tissue sampling and preparation, freeze-dried fine-needle punctates showed significantly higher enzyme activities of PFK and HOADH than freeze-dried liver sections or crude homogenates. Freeze-drying of fine needle biopsies appears to be a technique with good preservation of the enzyme activity. This is of significance for future metabolic studies also in humans.

3-Hydroxyacyl CoA Dehydrogenases↗
PubMed1977

Hydroxyacyl CoA dehydrogenase, an enzyme important in fat metabolism in different cell types in the islets of Langerhans.

The pancreatic islets show a remarkably high activity of L-3-hydroxy-acyl CoA dehydrogenase, an enzyme which operates in the fatty acid cycle by catalyzing the NAD+ oxidation of some of the degradation products. In order to study the distribution pattern of its activity within the islets, samples with different relative contents of A1-, A2- and B-cells were prepared and analyzed. The results show that it is unlikely that either the A1-cells or the enzymatically well equipped A2-cells contribute to the high activity values of the islets. In contrast, the experiments indicated that the high activity was due to the B-cells. After 72 hours starvation, leading to an increase in the serum free fatty acids, there was no change in the activity of the A2-cells, while the B-cells, however, showed a significant but moderate decrease in their activity. It is concluded that the B-cells are enzymatically equipped for the oxidation of fatty acid degradation products even in situations with diminished activity such as occurs during a decrease of the mitochondrial assembly.

3-Hydroxyacyl CoA Dehydrogenases↗
PubMed1978

Muscle metabolic profiles and fiber-type composition in some marine mammals.

1. Hexokinase, lactate dehydrogenase, 3-hydroxyacyl-CoA dehydrogenase, and malate dehydrogenase activities as well as fiber type composition were determined in skeletal muscles of the California sea lion (Zalophus californianus), the sea otter (Enhydra lutris), and the Pacific white-sided dolphin (Lagenorhynchus obliquidens). 2. The subcutaneous muscle of the sea lion had intermediate glycolytic and oxidative enzyme activities. 3. The locomotory muscles examined in the otter and porpoise did not contain a single predominant fiber type, but did have a well developed oxidative as well as glycolytic metabolic capacity.

3-Hydroxyacyl CoA Dehydrogenases↗
PubMed1977

Evidence for a complex of three beta-oxidation enzymes in Escherichia coli: induction and localization.

The enzymes for beta-oxidation of fatty acids in inducible and constitutive strains of Escherichia coli were assayed in soluble and membrane fractions of disrupted cells by using fatty acid and acyl-coenzyme A (CoA) substrates containing either 4 or 16 carbon atoms in the acyl moieties. Cell fractionation was monitored, using succinic dehydrogenase as a membrane marker and glucose 6-phosphate dehydrogenase as a soluble marker. Acyl-CoA synthetase activity was detected exclusively in the membrane fraction, whereas acyl-CoA dehydrogenase, 3-hydroxyacyl-CoA dehydrogenase, enoyl-CoA hydratase, and 3-ketoacyl-CoA thiolase activities that utilized both C4 and C16 acyl-CoA substrates were isolated from the soluble fraction. 3-Hydroxyacyl-CoA dehydrogenase, enoyl-CoA hydratase, and 3-ketoacyl-CoA thiolase activities assayed with both C4 and C16 acyl-CoA substrates co-chromatographed on gel filtration and ion-exchange columns and cosedimented in glycerol gradients. The data show that these three enzyme activities of the fad regulon can be isolated as a multienzyme complex. This complex dissociates in very dilute preparations; however, in those preparations where the three activities are separated, the fractionated species retain activity with both C4 and C16 acyl-CoA substrates.

3-Hydroxyacyl CoA Dehydrogenases↗
PubMed1979

Five different enzymatic activities are associated with the multienzyme complex of fatty acid oxidation from Escherichia coli.

The purified multienzyme complex of fatty acid oxidation from Escherichia coli was found to possess 3-hydroxyacyl-coenzyme A (CoA) epimerase and cis-delta3-trans-delta2-enoyl-CoA isomerase activities in addition to the previously identified enoyl-CoA hydratase, L-3-hydroxyacyl-CoA dehydrogenase, and 3-ketoactyl-CoA thiolase activities. Evidence is presented in support of the proposed association of all five enzyme activities with one protein which apparently is composed of two types of subunits and which can exist in several aggregated forms. The five component enzymes of the complex were rapidly inactivated by tris(hydroxymethyl)aminomethane, whereas they remained active in the presence of potassium phosphate.

3-Hydroxyacyl CoA Dehydrogenases↗