PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “GLYCEROLPHOSPHATE DEHYDROGENASE”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 289 records · Page 16Linked to original sources
PubMed1974

Phosphonomethyl analogues of phosphate ester glycolytic intermediates.

Analogues of dihydroxyacetone phosphate and of 3-phosphoglycerate were made in which the phosphate group, -O-PO(3)H(2), is replaced by the phosphonomethyl group, -CH(2)-PO(3)H(2). The analogue of dihydroxyacetone phosphate is a substrate for aldolase and glycerol 1-phosphate dehydrogenase (Stribling, 1974), but not for triose phosphate isomerase. The analogue of 3-phosphoglycerate oxidizes NADH under the combined action of 3-phosphoglycerate kinase and glyceraldehyde 3-phosphate dehydrogenase if ATP is added. Thus four out of the five glycolytic enzymes tested handle the phosphonomethyl compounds like the natural phosphates.

Adenosine Triphosphate↗
PubMed1976

Activity and androgenic control of glycolytic enzymes in the epididymis and epididymal spermatozoa of the rat.

1. Procedures were developed for the extraction and assay of glycolytic enzymes from the epididymis and epididymal spermatozoa of the rat. 2. The epididymis was separated into four segments for analysis. When rendered free of spermatozoa by efferent duct ligation, regional differences in enzyme activity were apparent. Phosphofructokinase, glycerol phosphate dehydrogenase and glucose 6-phosphate dehydrogenase were more active in the proximal regions of the epididymis, whereas hexokinase, lactate dehydrogenase and phosphorylase were more active in the distal segment. These enzymes were less active in the epididymis of castrated animals and less difference was apparent between the proximal and distal segments. However, the corpus epididymidis from castrated rats had lower activities of almost all enzymes compared with other epididymal segments. 3. Spermatozoa required sonication to obtain satisfactory enzyme release. Glycolytic enzymes were more active in spermatozoa than in epididymal tissue, being more than 10 times as active in the case of hexokinase, phosphoglycerate kinase and phosphoglycerate mutase. 4. The specific activities of a number of enzymes in the epididymis were dependent on the androgen status of the animal. These included hexokinase, phosphofructokinase, aldolase, glyceraldehyde phosphate dehydrogenase, phosphoglycerate kinase, pyruvate kinase, glycerol phosphate dehydrogenase, glucose 6-phosphate dehydrogenase, 6-phosphogluconate dehydrogenase and phosphorylase. 5. The caput and cauda epididymidis differed in the extent to which enzyme activities changed in response to an altered androgen status. The most notable examples were hexokinase, phosphofructokinase, aldolase, phosphoglycerate kinase, 6-phosphogluconate dehydrogenase and phosphorylase.

Animals↗
PubMed1991

Thyromimetic effect of peroxisomal proliferators in rat liver.

Amphipathic carboxylates, of varying hydrophobic backbones, which act as peroxisomal proliferators (aryloxyalkanoic acids, methyl-substituted dicarboxylic acid) induce in euthyroid or thyroidectomized rats, as well as in rat hepatocytes cultured in 3,5,3'-tri-iodo-L-thyronine (T3)-free media, liver enzyme activities that are classically considered to be thyroid-hormone-dependent (malic enzyme, mitochondrial alpha-glycerophosphate dehydrogenase, glucose-6-phosphate dehydrogenase and S14). The dose required in vivo for the thyromimetic effect of peroxisomal proliferators was 10(3)-fold higher than the dose of T3 required. Similarly, peroxisomal proliferators were active in culture in the range 1-100 microM compared with 1 nM for T3. Their maximal inductive capacities were, however, similar to or greater than that of T3. The thyromimetic effect of peroxisomal proliferators was only partially correlated with their capacities as inducers of liver peroxisomal enzymes. The thyromimetic effect with respect to liver malate dehydrogenase and S14 resulted from an increase in their mRNA contents. The increase in liver S14 mRNA was accounted for by transcriptional activation of the S14 gene. T3 binding to isolated liver nuclei or nuclear extract was competitively displaced by some but not all of the non-thyroidal inducers of the above liver activities. In contrast with the thyromimetic effect induced in liver cells, no increase in growth hormone mRNA was observed in cultured GH1 pituitary cells incubated in the presence of non-thyroidal amphipathic carboxylates. The characteristics of the thyromimetic effect of amphipathic carboxylic peroxisomal proliferators indicate that these agents may act as transcriptional activators of thyroid-hormone-dependent genes in the rat liver.

Animals↗
PubMed1992

Gene expression of lipid storage-related enzymes in adipose tissue of the genetically obese Zucker rat. Co-ordinated increase in transcriptional activity and potentiation by hyperinsulinaemia.

The genetically obese Zucker rat displays excessive fat storage capacity which is due to a tissue-specific increase in the activities of a number of lipid storage-related enzymes in adipose tissue. The aim of this study was to investigate the molecular mechanism responsible for this phenomenon. Lean (Fa/fa) and obese (fa/fa) Zucker rats were studied during the early stages of adipose tissue overdevelopment, both before (at 16 days of age) and after (at 30 days of age) the emergence of hyperinsulinaemia, in order to delineate the effects of the fatty genotype independently of those of hyperinsulinaemia. Lipoprotein lipase (LPL), glycerophosphate dehydrogenase (GPDH), glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and malic enzyme (ME) mRNA levels in the adipose tissue of lean and obese rats were assessed by Northern blot analysis, and the relative transcription rates of the corresponding genes were compared in the two genotypes by a nuclear run-on assay. In normoinsulinaemic 16-day-old pre-obese rats, mRNA levels were increased over control values (LPL, 5-fold; ME, 2-fold; GAPDH, 3-fold), in close correlation with genotype-mediated differences in enzyme activities. Stimulation of the transcription rates of the ME and GAPDH genes was observed in obese rats, which could fully account for differences in steady-state mRNA levels. At this age, GPDH activity, mRNA level and transcription rate were similar in the two genotypes. In hyperinsulinaemic 30-day-old obese rats, a 6-7-fold increase in both mRNA and the transcription rate of GPDH emerged, together with an amplification of the genotype-mediated differences observed in younger animals (GAPDH, 6-fold; ME, 7.9-fold; LPL, 10-fold). These results demonstrate that the obese genotype exerts a co-ordinated control on the expression of these genes in adipose tissue, mainly at the transcriptional level. This genotype effect is greatly amplified by the development of hyperinsulinaemia.

Adipose Tissue↗
PubMedDate not supplied

Effects of photoperiod and feeding level on perirenal adipose tissue metabolic activity and leptin synthesis in the ovariectomized ewe.

Leptin is secreted by adipose tissue and plays a pivotal role in regulating both body energy homeostasis and reproductive function in rodents. Among livestock, sheep is a seasonal breeder whose reproductive period is initiated by short daylength. We show that plasma leptin and leptin gene expression in perirenal adipose tissue were decreased when ovariectomized Lacaune ewes were exposed to short days (8 versus 16 h light/d). This effect of the photoperiod occurred despite the nutritional status, with leptin levels lower in underfed than in refed ewes, and without significant changes in perirenal fat mass and adipocyte size. Plasma prolactin and leptin followed a similar pattern suggesting a relationship between the two hormones. These findings indicate, for the first time, that adipose tissue leptin is modulated by daylength independently of food intake, body fatness and gonadal activity. Furthermore, plasma non-esterified fatty acids of underfed ewes subjected to short days were more elevated than for underfed ewes on long days. On the other hand, refed ewes placed under long daylength tended to have a higher adipose tissue lipogenic activity than refed ewes on short days. We propose that these adaptations of leptin production and lipogenic activity with long photoperiod are of physiological significance for body fat deposition, which naturally occurs during long days when food is abundant. Conversely, a low leptin level during short days may enhance the sensitivity to food deprivation during the natural reproductive season, where any food shortage would decrease plasma leptin under a threshold critical for reproduction. Furthermore, in this situation, the observed enhanced ability to mobilize body fat may be related to the necessity to cope with energy shortage.

Adipose Tissue↗
PubMed1976

The effects of estradiol administration of the hepatic activities of some enzymes of carbohydrate, amino acid and lipid metabolism in the immature pullet.

Two experiments were performed to examine the effects of intramuscular estradiol administration on the hepatic specific activities of some enzymes of lipid, carbohydrate and amino acid metabolism in the immature fowl. Estradiol increased the specific activities of the hepatic lipogenic enzymes, ATP citrate lyase and malate dehydrogenase (decarboxylating) (NADP), but had no effects on the activities of the glycolytic, gluconeogenic and amino acid metabolising enzymes except for pyruvate kinase and glutamate dehydrogenase which were reduced in activity in both experiments. The results indicate that the estrogen-induced increase in hepatic lipid biosynthesis is due to a specific effect on lipid metabolism and not to a general increase in liver metabolism.

ATP Citrate (pro-S)-Lyase↗
PubMed1973

Conformations of diphosphopyridine coenzymes upon binding to dehydrogenases.

The binding of oxidized as well as reduced coenzyme to some dehydrogenases has been studied under different concentration ratios and temperatures by nuclear magnetic resonance spectroscopy. A significant difference in the spectral behavior between DPN(+) and DPNH upon binding is interpreted in terms of fast and slow on-off rates relative to the nuclear magnetic resonance time scale in the binding of these two coenzymes. Significant downfield shifts of DPN(+) were observed upon binding, comparable in magnitude to those expected upon opening (destacking) of the coenzymes in the case of chicken-muscle and lobster-tail lactate dehydrogenase (EC 1.1.1.27) and yeast alchol dehydrogenase (EC 1.1.1.1.). A preliminary survey of several other dehydrogenases is consistent with these findings. In the case of 3-phosphoglyceraldehyde dehydrogenase, there is a possibility that the coenzyme exists in the folded form.

Alcohol Oxidoreductases↗
PubMed1989

Short-range genetic structure of Drosophila melanogaster populations in an Afrotropical urban area and its significance.

Alcohol dehydrogenase (Adh) (alcohol:NAD+ oxidoreductase, EC 1.1.1.1) gene frequencies and ethanol tolerance in Drosophila melanogaster are known to exhibit long-range latitudinal variations on different continents; this has led to the argument that the clines are adaptive. Accordingly, tropical populations are characterized both by a low frequency of Adh-F and by a low ethanol tolerance. In the urban area of Brazzaville (Congo) under an equatorial African climate, an original genetic structure of local populations has been found: Adh-F frequency varies from 3% to 90% when countryside and brewery populations are compared. This variation is accompanied by an increase of ethanol tolerance (from 6% to 13% alcohol). Such differences, which have remained stable for the past 3 years, were observed between collection sites less than 1 km apart. Two other enzyme loci exhibited a correlated variation with Adh-F--i.e., an increase of the S allele of glycerol-3-phosphate dehydrogenase (NAD+) (sn-glycerol-3-phosphate:NAD+ 2-oxidoreductase, EC 1.1.1.8) and of the F allele of glucose-6-phosphate dehydrogenase (D-glucose-6-phosphate:NADP+ 1-oxidoreductase, EC 1.1.1.49). Such observations suggest very strong selective pressures exerted by environmental ethanol that oppose the gene flow due to adult dispersal between contiguous habitats. A functional relationship between the polymorphisms of the three enzyme loci seems likely, and a metabolic interaction involving NAD and NADP cofactors is proposed.

Alleles↗
PubMed1999

What controls glycolysis in bloodstream form Trypanosoma brucei?

On the basis of the experimentally determined kinetic properties of the trypanosomal enzymes, the question is addressed of which step limits the glycolytic flux in bloodstream form Trypanosoma brucei. There appeared to be no single answer; in the physiological range, control shifted between the glucose transporter on the one hand and aldolase (ALD), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), phosphoglycerate kinase (PGK), and glycerol-3-phosphate dehydrogenase (GDH) on the other hand. The other kinases, which are often thought to control glycolysis, exerted little control; so did the utilization of ATP. We identified potential targets for anti-trypanosomal drugs by calculating which steps need the least inhibition to achieve a certain inhibition of the glycolytic flux in these parasites. The glucose transporter appeared to be the most promising target, followed by ALD, GDH, GAPDH, and PGK. By contrast, in erythrocytes more than 95% deficiencies of PGK, GAPDH, or ALD did not cause any clinical symptoms (Schuster, R. and Holzhütter, H.-G. (1995) Eur. J. Biochem. 229, 403-418). Therefore, the selectivity of drugs inhibiting these enzymes may be much higher than expected from their molecular effects alone. Quite unexpectedly, trypanosomes seem to possess a substantial overcapacity of hexokinase, phosphofructokinase, and pyruvate kinase, making these "irreversible" enzymes mediocre drug targets.

Adenosine Triphosphate↗
PubMed1969

Unusually high mitochondrial alpha glycerophosphate dehydrogenase activity in rat brown adipose tissue.

Brown adipose tissue of the rat has been found to have an unusually high activity of mitohondrial alpha-glycerophosphate dehydrogenase (alpha-GPD) when assayed both by a histochemical staining procedure and by a quantitative biochemical method with isolated mitochondria. In contrast to succinic, glutamic, and beta-hydroxybutyrate dehydrogenases, all mitochondrial enzymes, the activity of alpha-GPD in brown fat was 10 times that in liver, more than 20 times that in white adipose tissue, and 9 times that in kidney. The soluble NAD-linked alpha-GPD was also higher in brown adipose tissue than in white adipose tissue, liver, or kidney, but the differences were much less marked. The possible importance of the high activity of mitochondrial alpha-GPD in the regulation of synthesis of esterified lipid and in thermogenesis in brown fat is discussed.

Adipose Tissue↗
PubMed1974

The alpha-glycerophosphate cycle in Drosophila melanogaster. IV. Metabolic, ultrastructural, and adaptive consequences of alphaGpdh-l "null" mutations.

"Null" mutations previously isolated at the alphaGpdh-1 locus of Drosophila melanogaster, because of disruption of the energy-producing alpha-glycerophosphate cycle, severely restrict the flight ability and relative viability of affected individuals. Two "null" alleles, alphaGpdh-1(BO-1-4), and alphaGpdh-1(BO-1-5,) when made hemizygous with a deficiency of the alphaGpdh-1 locus, Df(2L)GdhA, were rendered homozygous by recombination with and selective elimination of the Df(2L)GdhA chromosome. After over 25 generations, a homozygous alphaGpdh-1(BO-1-4) stock regained the ability to fly despite the continued absence of measurable alphaGPDH activity. Inter se heterozygotes of three noncomplementing alphaGpdh-1 "null" alleles and the "adapted" alphaGpdh-1(BO-1-4) homozygotes were examined for metabolic enzymatic activities related to the energy-producing and pyridine nucleotide-regulating functions of the alpha-glycerophosphate cycle in Drosophila. The enzyme functions tested included glyceraldehyde-3-phosphate dehydrogenase, cytoplasmic and soluble malate dehydrogenase, lactate dehydrogenase, mitochondrial NADH oxidation, oxidative phosphorylation, and respiratory control with the substrates alpha-glycerophosphate, succinate, and pyruvate. These activities in any of the mutant genotypes in early adult life were indistinguishable from those in the wild type. There was, however, a premature deterioration and atrophy of the ultrastructural integrity of flight muscle sarcosomes observed by electron microscopy in the "null" mutants. These observations were correlated with a decrease in state 3 mitochondrial oxidation with alpha-glycerophosphate, succinate, and pyruvate, as well as with loss of respiratory control in adults as early as 2 wk after eclosion. Such observations, which normally are seen in aged dipterans, were accompanied by premature mortality of the mutant heterozygotes. The adapted alphaGpdh-1(BO-1-4) was identical with wild type in each of the aging characters with the single exception of lowered rates of mitochondrial oxidative phosphorylation.

Adaptation, Biological↗
PubMed1990

Di(2-ethylhexyl)phthalate alters carbohydrate enzyme activities and foci incidence in rat liver.

The effect of di(2-ethylhexyl)phthalate (DEHP) on diethylnitrosamine (DEN)-initiated preneoplastic liver lesions with expression of gamma-glutamyltranspeptidase (GGTase) and loss of adenosine triphosphatase (ATPase) as well as alterations of hepatic carbohydrate metabolism in male and female Sprague-Dawley rats have been investigated. Two treatment schedules have been compared with respect to their sensitivity by the histochemical demonstration of preneoplastic islands and by the biochemical determination of alterations in enzyme activities of liver homogenates and of serum, the last indicating hepatotoxicity. For initiation, a single dose of DEN was given, followed by treatment with various doses of DEHP given three times weekly by gavage for 7 or 11 consecutive weeks. As histochemical enzyme markers, the expression of positive GGTase as well as the deficiency in ATPase were used for identification of liver foci. The weanling female rats (protocol A) were found to be more sensitive to the carcinogenic effect of DEN in view of foci incidence than the mature male rats which underwent partial hepatectomy prior to DEN application. The administration of 200 mg DEHP/kg body wt increased the incidence of ATPase-deficient foci in both male and female rats; however, concentrations of 1000 and 2000 mg DEHP/kg decreased the incidence of liver foci. The number of foci with expression of GGTase was only slightly increased in female rats following a DEHP concentration of 50 mg/kg, and 200 mg/kg body wt. DEHP alone did not induce preneoplastic lesions that could be identified by these two markers. Biochemical investigations indicate that DEHP alters the metabolic pattern in liver. An increase of the NADP-linked enzymes glucose-6-phosphate dehydrogenase (G6PDH), malic enzyme, extra-mitochondrial ICDH as well as an enhancement of NAD-dependent alpha-G3PDH and lactate dehydrogenase were found following DEHP administration. On the other hand the glycolytic enzymes pyruvate kinase (PK) and enolase as well as the gluconeogenetic enzyme fructose-1,6-bisphosphatase (FBPase) were significantly reduced. In protocol B (male rats) the reactions of PK, FBPase and malic enzyme were more altered after DEHP exposure than in protocol A, while the activity of G6PDH was more increased in protocol A. Most enzymes being involved in the carbohydrate metabolism are influenced by DEHP in a dose-dependent manner. There was no increase in serum FBPase activity in both male and female rats after DEHP treatment but a reduction of glutamate-oxalate-transaminase and glutamate-pyruvate-transaminase activities was observed.(ABSTRACT TRUNCATED AT 400 WORDS)

Adenosine Triphosphatases↗