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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In this study, we have examined the relationship between creatine phosphokinase (CPK), a biochemical measure of human sperm quality (Huszar et al., 1988a,b, 1990; Huszar and Vigue, 1994), and a marker for the presence of residual cytoplasm in human spermatozoa, glucose-6-phosphate dehydrogenase (G6PDH). We then determined whether the diagnostic potential of these enzymes was related to the capacity of the sperm suspensions to generate reactive oxygen species (ROS) and/or the presence of leukocytes and precursor germ cells. Across the data set as a whole, G6PDH and CPK were highly correlated with each other and, to a lesser extent, with the generation of ROS. Contamination of the sperm suspensions with leukocytes might have contributed to these associations, since the presence of such cells was also significantly correlated with CPK, G6PDH, and ROS. However, even after the leukocytes had been carefully removed, G6PDH was still highly correlated with CPK (r = 0.794), indicating that both criteria were providing similar information of the cytosolic component of human sperm suspensions. In the absence of leukocyte contamination, CPK and G6PDH activities were also correlated with the presence of precursor germ cells, and this association may, in part, explain the diagnostic value of these criteria. An additional component of their prognostic value may be reflected in the statistically significant association observed between G6PDH activity and ROS generation. A possible mechanism for such an association is suggested, which should be amenable to experimental verification.
Mol Reprod Dev 1994 Nov
PMID:Relationships between biochemical markers for residual sperm cytoplasm, reactive oxygen species generation, and the presence of leukocytes and precursor germ cells in human sperm suspensions. 788 66

This study reports the effects of alloxan induced diabetes on glucose metabolism enzymes viz. Hexokinase, Lactate dehydrogenase, and Glucose-6-phosphate dehydrogenase from discrete brain regions. Enzymes activity was assayed from hypothalamic areas such as medial preoptic area and median eminence-arcuate region which have gonadotropin releasing hormone cell bodies and their terminals, respectively and other brain regions like septum, amygdala, hippocampus, and thalamus. In all the areas studied, induction of diabetes resulted in a significant decrease in particulate bound HK activity, whereas soluble HK, LDH and G6PDH activity showed increase at 3, 8, 15 and 28 days intervals. Insulin treatment of diabetic rats led to recovery in enzyme activity. Blood glucose levels increased significantly after induction of diabetes and recovery was seen after insulin treatment. The present results suggest that altered cerebral glucose metabolism may also be responsible for reproductive failure observed in diabetic rats.
Mol Cell Biochem 1994 Dec 21
PMID:Changes in glucose metabolism from discrete regions of rat brain and its relationship to reproductive failure during experimental diabetes. 789 76

Normal human erythrocytes suspended in isotonic saline at 0.5 haematocrit displayed, after 30 min exposure to 1 mM tert-butylhydroperoxide at 37 degrees C, a marked increase of NADPH, while the concentration of the other adenine nucleotides was almost unchanged. Hereditary Spherocytosis and glucose-6-phosphate dehydrogenase-deficient red blood cells exhibited, under basal conditions, higher levels of most of the nucleotides assayed and significant amounts of hypoxanthine. Treatment with tert-butylhydroperoxide caused, in glucose-6-phosphate dehydrogenase-deficient erythrocytes, a pronounced decrease of ADP and of AMP levels, a substantial invariance of other adenine nucleotides and a considerable raise of hypoxanthine. On the contrary, Hereditary Spherocytosis erythrocytes exhibited, after oxidative stress, increased levels of ADP and of AMP, a slight decrease of ATP and an accumulation of hypoxanthine similar to that found in enzyme-deficient red cells. In both the pathologic erythrocytes the addition of phosphate during the oxidative treatment resulted in a lower formation of hypoxanthine, while the presence of 10 mM glucose, fully prevented its appearance.
Biochem Mol Biol Int 1994 Jan
PMID:Variations of adenine nucleotide levels in normal and pathologic human erythrocytes exposed to oxidative stress. 801 94

Utilization of highly enriched preparations of steroidogenic Leydig cells have proven invaluable for studying the direct effects of various hormones and agents on Leydig cell function in vitro. However, recent work indicates that isolated Leydig cells are often subjected to oxygen (O2) toxicity when cultured at ambient (19%) oxygen concentrations. Because intracellular antioxidants play an important role in protecting cells against oxygen toxicity, we have investigated the intracellular antioxidant defense system of isolated Leydig cells. The cellular levels of several antioxidants including catalase, glucose-6-phosphate dehydrogenase (G-6-PDH), superoxide dismutase (SOD) of the Cu/Zn & Mn variety, glutathione peroxidase, glutathione reductase and total glutathione were quantitated using enriched populations of Leydig cells isolated from adult male guinea pig testes. Compared to whole testicular homogenates, Leydig cells contained significantly (P < 0.01) less G-6-PDH, total SOD, glutathione reductase and total glutathione, but significantly (P < 0.001) more glutathione peroxidase. Compared to hepatic values previously reported in the guinea pig, Leydig cells contain nearly 400 times less catalase, about 14 times less glutathione peroxidase and almost 11 times less glutathione reductase. Since G-6-PDH and glutathione reductase are both necessary to regenerate reduced glutathione (GSH) which couples with glutathione peroxidase to breakdown hydrogen peroxide (H2O2) under normal conditions, it is plausible that the oxygen toxicity observed in isolated Leydig cells is due to the intracellular accumulation of H2O2.(ABSTRACT TRUNCATED AT 250 WORDS)
Mol Cell Biochem 1993 Sep 08
PMID:The antioxidant defense system of isolated guinea pig Leydig cells. 810 85

The pathways of pectin and galacturonate catabolism in Erwinia chrysanthemi converge to form a common intermediate, 2-keto-3-deoxygluconate, which is phosphorylated to form 2-keto-3-deoxy-6-phosphogluconate (KDGP) and then cleaved by the aldolase encoded by the kdgA gene. We cloned the kdgA gene of the E. chrysanthemi strain 3937 by complementing an Escherichia coli kdgA mutation, using an RP4-derivative plasmid. Restriction mapping of the kdgA region and isolation of kdgA-lac fusions allowed the more precise localization of the kdgA gene and determination of its transcriptional direction. The nucleotide sequence of the kdgA region indicated that the kdgA reading frame is 639 bases long, corresponding to a protein of 213 amino acids with a molecular mass of 22,187 Da. Comparison of the deduced primary amino acid sequences of the E. chrysanthemi KDGP-aldolase to the E. coli, Zymomonas mobilis and Pseudomonas putida enzymes showed that they are highly conserved. The E. chrysanthemi kdgA structural gene begins 153 bases downstream of an open reading frame that has a high homology with the zwf E. coli gene encoding glucose-6-phosphate dehydrogenase. The zwf gene is also linked to eda (kdgA) in E. coli and P. putida but genetic organization is different. Regulation of zwf and kdgA expression in E. chrysanthemi was analysed using lacZ fusions. The expression of zwf is independent of the growth rate, but is repressed in the presence of glucose. Induction of kdgA by pectin-degradation products is mediated in vivo by the negative regulatory gene kdgR, which also controls all the steps of pectin degradation.(ABSTRACT TRUNCATED AT 250 WORDS)
Mol Microbiol 1994 Jan
PMID:Molecular analysis of the Erwinia chrysanthemi region containing the kdgA and zwf genes. 814 47

We have characterized the expression of allelic variants of X-linked glucose 6-phosphate dehydrogenase (G6PD) in aorta from homozygous, hemizygous, and heterozygous baboons (Papio hamadryas). Fibrous plaques from heterozygous baboons fed a high cholesterol, saturated fat diet contained distributions of G6PD allelic variants that differed from those of normal arterial wall and fatty streaks. The skewed allelic expression patterns in fibrous plaques of heterozygotes reflect decreased cellular heterogeneity in advanced vascular lesions. The tendency toward cellular monotypism in fibrous plaques is similar to that present in advanced human atherosclerotic lesions. Our results suggest that G6PD heterozygous baboons are a unique primate model for investigating the cellular origin of proliferating smooth muscle cells in atherosclerotic plaques.
Exp Mol Pathol 1993 Oct
PMID:A primate model of monotypism in atherosclerotic lesions. 822 12

A characterization of cell lines that we derived from morulae (three lines), blastocysts (two lines), and the inner cell mass (ICM) is given. The karyotype of all the lines was normal; the genotype of four lines was XX, and four lines were genotypically XY. The pluripotencies and commitment status of the derived lines were estimated. First, there were not less than two-thirds of cells in the populations of the lines derived from morulae and the ICM with both Xs active; 70-100% of cells of the blastocyst-derived lines had one of the Xs in an inactive state. The activity of glucose-6-phosphate dehydrogenase (G6PD) in the lines (genotype XX) derived from morulae and ICM was found to be twofold higher than in lines with genotype XY, and G6PD activity was the same in the blastocyst-derived XX lines and XY lines. Second, when injected intraperitoneally into athymic mice, morulae- and ICM-derived cells gave rise to simple and complex embryoid bodies (EB) resembling to typical "cystic" mouse EBs. Third, when injected subcutaneously to athymic mice, the ICM- or morula-derived cells gave rise to typical teratomas containing derivatives of the three germ layers and components of organogenesis. Comparisons of cell lines of different derivations demonstrated that the pluripotencies of the ES cells derived from morulae or the ICM are higher than those of blastocyst derivation.
Mol Reprod Dev 1993 Oct
PMID:Embryonic stem cells derived from morulae, inner cell mass, and blastocysts of mink: comparisons of their pluripotencies. 825 64

Tandem insertions of defective P elements (1.15 kb KP and 0.6 kb core P) accelerate the transcription rate of the glucose-6-phosphate dehydrogenase (G6PD) gene in Drosophila melanogaster. In this report, we have analyzed the activation mechanism of the G6PD promoter by in vitro transcription and gel retardation assays. Results showed that one cis-acting region in the core P and two such regions in the KP are associated with activation of the G6PD promoter, and that putative transcriptional regulatory protein(s) which specifically bind to each of the cis-acting regions are present in nuclear extracts of Canton S embryos. On the other hand, the P elements do not activate the normal actin 5C promoter, but activate the promoter when the 20 bp sequence around the G6PD transcription start site is placed in front of the promoter. It appears that the GC-rich region in this 20 bp sequence is required for the activation.
Mol Gen Genet 1993 Dec
PMID:Transcriptional activation of the Drosophila melanogaster glucose-6-phosphate dehydrogenase gene by insertion of defective P elements. 826 38

We have isolated and determined the nucleotide sequences for cDNA clones encoding glucose-6-phosphate dehydrogenase (G6PD) and 6-phosphogluconate dehydrogenase (6PGD) from the medfly Ceratitis capitata. The derived amino acid sequences for G6PD and 6PGD are presented and compared with G6PDs and 6PGDs from other species. The codon usage of the cDNA clones has little bias with the notable exceptions of arginine, glycine and leucine. The chromosomal location of the genes for 6PGD and G6PD were determined by in situ hybridization to salivary gland polytene chromosomes. This localization orients a genetic map of enzymatic loci and illustrates a remarkable similarity in the intra chromosomal order of homologous genes between Drosophila melanogaster and medfly.
Insect Mol Biol 1993
PMID:Isolation of cDNAs encoding 6-phosphogluconate dehydrogenase and glucose-6-phosphate dehydrogenase from the mediterranean fruit fly Ceratitis capitata: correlating genetic and physical maps of chromosome 5. 826

Effects of prolactin(Prl), bromocriptine(Br), testosterone propionate (TP), dihydrotestosterone (DHT) and combinations of these androgens with Prl/Br on the maximum catalytic capacities of seminal vesicular enzymes involved in the glycolytic and pentose phosphate pathways in castrated mature monkeys were studied. Castration decreased the activities of all of the enzymes studied such as hexokinase(HK), 6-phosphofructokinase(PFK), glyceraldehyde-3-phosphate dehydrogenase(G3PD), pyruvate kinase(PK), glucose 6-phosphate dehydrogenase (G6PD) and 6-phosphogluconate dehydrogenase(6PGD) in the seminal vesicles. Prl restored the activities of all of the enzymes to their normal values except G3PD. TP/DHT maintained all the enzyme activities at the normal tissue intact level. Prl given along with androgens further enhanced the androgen action with regard to all the enzymes activities except G3PD. Br decreased all of the enzymes but Br with androgens maintained all the enzyme activities at the normal level. Castration decreased significantly serum T/DHT titres but Prl did not alter Prl levels. Prl+TP/DHT elevated Prl levels. Br alone decreased serum Prl, T and DHT titres, but Br+TP/DHT decreased only Prl, elevated T and maintained DHT levels. These results suggest that Prl has a direct as well as a synergistic action with androgens on the activities of the enzymes of glycolysis and pentose phosphate pathways in the seminal vesicles of castrated monkeys.
Biochem Mol Biol Int 1993 Oct
PMID:Effects of prolactin and androgens on enzymes of carbohydrate metabolism in seminal vesicles of castrated mature bonnet monkeys, Macaca radiata. 827 11


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