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Query: UMLS:C0011570 (depression)
 172,036 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Ultrastructural morphometric and biochemical studies were conducted on hepatic mitochondria from control rats and rats treated in vivo with arsenate to examine changes in interrelationships between mitochondrial structure and biochemical functions. Morphometric analysis disclosed an over-all 1.2-fold increase in the relative mitochondrial volume density and 1.4-fold increase in the surface density of the inner mitochondrial membrane of arsenate-exposed rats. These structural changes were associated with a 1.5-fold increase in 14C-leucine incorporation into all mitochondrial proteins, which was primarily associated with the acid-insoluble membranous fraction. Mitochondria from arsenate-treated rats showed a marked disruption of normal conformational behavior with depression of nicotinamide adenine dinucleotide (NAD)-linked substrate oxidation and a resulting in vivo increase in the mitochondrial [NAD] to [NADH] ratio. Observed changes in mitochondrial membranes from arsenate exposure also resulted in 1.5- to 2-fold increases in the specific activities of the membrane marker enzymes monoamine oxidase, cytochrome oxidase, and Mg2+-ATPase. Activity of malate dehydrogenase, which is localized in the mitochondrial matrix, was unchanged. The results of this study demonstrate a positive quantitative in vivo correlation between mitochondrial structure and function and indicate a marked dependency upon membrane integrity for normal maintenance of the specific biologic activities performed by this organelle in vivo.
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PMID:Studies of hepatic mitochondrial structure and function: morphometric and biochemical evaluation of in vivo perturbation by arsenate. 49 44

Marked disorders of energy metabolism in the heart muscle simultaneously with the development of ulcerous lesions of the stomach were revealed in animals which had suffered an emotional-pain stress (EPS). These disorders are displayed in the fact that two hours after EPS, the glycogen reserve in the animal's myocardium diminishes, resynthesis of glycogen and oxidation of the main substrates of the tricarboxylic acid cycle are inhibited, and malate dehydrogenase and possibly other dehydrogenase systems of the mitochondria are partly inactivated. Such decrease in the activity of the metabolic tracts is attended by depression of the force and rate of cardiac contractions revealed on inducing a high rate of contractions. The preliminary administration of sodium gammaoxybutyrate to a considerable extent prevents all the changes in the animal's myocardium occurring due to the effect of EPS.
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PMID:[Myocardial energy metabolic disorders in emotional-pain stress and the prevention of these disorders by using sodium gamma-oxybutyrate]. 56 26

Cytochysiological and cytophotometric studies carried out for 9-11 days on rabbits showed that hypoxic hypoxia (equivalent to the altitude of 5000 m) led to depression of the phagocytic activity of the alveolar macrophages. Simultaneously macrophages of the lungs displayed an increase in the activity of lactic and glucoso-6-phosphoric dehydrogenases, and a reduction of malic dehydrogenase activity. Experiments carried out in vitro with the macrophages of guinea pig lungs demonstrated that cell respiration served as the principal source of energy required for phagocytosis. A conclusion was drawn that respiratory inhibition in hypoxia was not compensated by activation of glucolysis and glucose metabolism in the pentose shunt and was the principal cause of disturbances of the phagocytic function of macrophages of the lungs.
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PMID:[The effect of hypoxia on the function and metabolism of alveolar macrophages]. 112 1

Since glycogen overloading is one of the outstanding features of the diabetic liver, a series of investigations were undertaken to find an enzymatic explanation of this feature. Three groups of patients were studied: non diabetics submitted to liver biopsy during surgery (group A); non diabetics submitted to percutaneous liver biopsy (group B). In both these groups G-6-PDH, PK and MDH were assayed, all these being adaptive enzymes of intermediate metabolism. Results were expressed as muU/100 mg proteins. The significant finding of the comparison of these two groups was the low concentration of these enzymes in surgical biopsies. The depression was such that for G-6-PDH the concentration was more than 10 times less in surgical specimens as compared to percutaneous ones, whereas for PK it was almost 10 times less. In view of these findings no further surgically obtained biopsy material was used in this study. The third group (C) included insulin-dependent diabetics in good metabolic control from whom percutaneous liver biopsies were obtained for the assay of the same enzymes as above and in order to compare the results with those of group B. All three enzymes were diminished in diabetics, the difference being statistically significant for G-6-PDH and PK, not for MDH in view of the wide dispersion of the values found. Comparison and analysis of these results lead to the conclusion that in view of the low concentration of these enzymes in diabetics, glucose utilization in the liver cell must be presumed to be increased via other metabolic pathways.
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PMID:The liver in human diabetes. Concentration of some induced enzymes. 123 63

Isolated hepatocytes from hypothyroid, euthyroid and hyperthyroid rats have been employed to investigate the relative importance of reducing-equivalent shuttles for the transfer of hydrogen between cytoplasm and mitochondria during simultaneous ureogenesis and gluconeogenesis. In cells from hypothyroid animals, a 58% depression of glucose formation and 68% reduction in ureogenesis were induced by n-butylmalonate, an inhibitor of the malate shuttle. A more reduced state of the cytoplasmic compartment and a substantial fall in the concentrations of pyruvate, aspartate, alanine and glutamate accompanied this inhibition. Preincubation of cells with n-butylmalonate yielded greater inhibitory effects than observed in the absence of preincubation. The inhibitory effects on gluconeogenesis and ureogenesis were less in cells from euthyroid rats and were very much reduced in the case of glucose synthesis and absent in the case of ureogenesis, in cells from hyperthyroid rats. It is inferred that both the malate-aspartate and alpha-glycerophosphate shuttles may function in the transfer of reducing equivalents from cytoplasm to mitochondria during ureogenesis in hepatocytes. The major inhibition by n-butylmalonate of glucose and urea synthesis in hepatocytes from hypothyroid rats is due to the diminished activity of the alpha-glycerophosphate shuttle in these cells. Moreover, it follows that the NADH arising from the cytoplasmic malate dehydrogenase-catalysed reaction is accessible to both the malate-aspartate shuttle and the alpha-glycerophosphate shuttle.
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PMID:Reducing-equivalent transfer to the mitochondria during gluconeogenesis and ureogenesis in hepatocytes from rats of different thyroid status. 135 45

Biochemical investigations were performed on cardiac muscle samples from seven dogs with cardiomyopathy and on cardiac muscle from a varied selection of normal dogs. Biochemical examination of cardiac muscle from clinical cases of cardiomyopathy revealed that the concentrations of three enzymes were significantly altered. These were, catalase, succinic dehydrogenase and malate dehydrogenase. Depressed enzyme concentrations were recorded from both ventricles but were significant only on the left for catalase, on the right for malate dehydrogenase and in both ventricles for succinic dehydrogenase although the depression in this case was also greater on the right.
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PMID:Biochemical investigations of cardiomyopathy in the dog. 362 75

The activity of NAD-linked alpha-glycerol-3-phosphate dehydrogenase (NAD-G3PDH; EC 1.1.1.8) was depressed by 35% when the thyroid hormone 3,3',5-triiodo-L-thyronine (20 micrograms/liter) was added to the serum-free, hormonally supplemented medium of cultured neonatal rat heart cells. The degree of depression was greater (65%) when the medium contained normal serum levels of hydrocortisone and insulin. There is a dramatic inverse dose-response relationship between triiodothyronine levels and NAD-G3PDH activity. The classic elevation by thyroid hormones of the FAD-linked alpha-glycerol-3-phosphate dehydrogenase (FAD-G3PD; EC 1.1.99.5) was observed concurrently. The medium-glucose depletion rate in triiodothyronine-free cells was depressed 32% through 11 days-in-culture, indicating reduced glycolytic activity. The activities of nine other metabolically important enzymes which were measured during this study, including hexokinase, glucose-6-phosphate dehydrogenase, 6-phosphogluconate dehydrogenase, phosphofructokinase, pyruvate kinase, malate dehydrogenase, NAD-isocitrate dehydrogenase, NADH cytochrome c reductase, and succinic cytochrome c reductase, did not respond to varying triiodothyronine concentrations.
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PMID:Triiodothyronine depresses the NAD-linked glycerol-3-phosphate dehydrogenase activity of cultured neonatal rat heart cells. 669 42

The effect of clofibrate (Atromid S, ethyl-2-(4-chlorophenoxy)-2-methylpropionate) administration for 7 days to rats on lipogenesis and on some lipogenic enzyme activities in brown adipose tissue (BAT), liver and white adipose tissue (WAT) was examined. As compared to control rats the rate of lipogenesis in BAT in the clofibrate-treated animals was significantly decreased. The rate of liver lipogenesis increased slightly, whereas lipogenesis in the WAT was not affected by clofibrate. In BAT, the drug treatment resulted in depression of fatty acid synthase, ATP-citrate lyase, malic enzyme, glucose 6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase activities. The activity of liver fatty acid synthase did not change, ATP-citrate lyase activity slightly decreased, whereas the activity of malic enzyme significantly increased in this organ after clofibrate feeding. The ATP-citrate lyase activity in WAT decreased, while fatty acid synthase and other lipogenic enzymes were not changed after clofibrate feeding. Clofibrate treatment did not influence the activity of NADP-linked isocitrate dehydrogenase and malate dehydrogenase (enzymes not linked directly to lipogenesis), either in BAT, liver or WAT. The data presented suggest that the hypolipidaemic effect of clofibrate in the rat may be due (possibly among other mechanisms) to reduction of the rate of fatty acid synthesis in BAT but not in the liver and WAT.
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PMID:Inhibition of lipogenesis in rat brown adipose tissue by clofibrate. 824 Apr 2

The activities of the enzymes involved in the malate-aspartate shuttle were measured in peripheral leucocytes of dogs with type 1 diabetes mellitus. In the diabetic dogs, fasting plasma glucose concentrations were twofold greater than control levels despite insulin injections and the activities of malate dehydrogenase (MDH), which plays a crucial role in the malate-aspartate shuttle, were decreased remarkably. The cytosolic ratio of MDH/lactate dehydrogenase (LDH) activity (M/L ratio) in leucocytes of the diabetic dogs was significantly lower than that of normal control dogs. The decrease of the M/L ratio appeared to reflect depression of energy metabolism in leucocytes of the diabetic dogs. The M/L ratio may be a useful parameter to evaluate metabolic conditions in diabetic dogs.
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PMID:Decrease in malate dehydrogenase activities in peripheral leucocytes of type 1 diabetic dogs. 1258 44

The activities of the enzymes in the malate-aspartate shuttle were measured in peripheral leucocytes of spontaneous type 1 diabetic dogs and cats treated with insulin injections. In the diabetic dogs and cats, fasting plasma glucose concentrations were three- or fourfold greater than the control levels in spite of insulin injections and the activities of cytosolic malate dehydrogenase (MDH), one of pivotal enzymes in the malate-aspartate shuttle, were remarkably lower than the controls. Depressed expression of cytosolic MDH mRNA was confirmed by RT-PCR analysis in the diabetic animals. The cytosolic ratio of MDH/lactate dehydrogenase (LDH) activity (M / L ratio) in leucocytes of the diabetic animals was significantly lower than that of normal control animals. The smaller M / L ratio appeared to reflect depression of energy metabolism in the diabetic animals. Intrinsically lower and further decreased MDH activities may be factors that induce insulin resistance observed in diabetic cats.
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PMID:Malate dehydrogenase activities are lower in some types of peripheral leucocytes of dogs and cats with type 1 diabetes mellitus. 1550 Aug 38


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