Effects of insulin, glucocorticoids and thyroid hormones on the activities of key enzymes of glycolysis, glutaminolysis, the pentose-phosphate pathway and the Krebs cycle in rat macrophages

1992 ◽  
Vol 135 (2) ◽  
pp. 213-219 ◽  
Author(s):  
L. F. B. P. Costa Rosa ◽  
Y. Cury ◽  
R. Curi
Keyword(s):  
Thyroid Hormones ◽  
Pentose Phosphate Pathway ◽  
Culture Medium ◽  
Citrate Synthase ◽  
Inflammatory Responses ◽  
Krebs Cycle ◽  
Pentose Phosphate ◽  
Macrophage Phagocytosis ◽  
And Function ◽  
Glucose 6 Phosphate Dehydrogenase

ABSTRACT In the present study the effects of insulin, glucocorticoids and thyroid hormones on macrophage metabolism and function were investigated. The maximum activities of hexokinase, glucose-6-phosphate dehydrogenase, glutaminase and citrate synthase were determined in macrophages obtained from hormonetreated rats and those cultured for a period of 48 h in the presence of hormones. Macrophage phagocytosis was markedly inhibited by dexamethasone and thyroid hormones, remaining unchanged when insulin was added to the culture medium, however. The changes in the enzyme activities caused by hormone treatments of the rats were very similar to those found in culture. Insulin enhanced citrate synthase and hexokinase activities and diminished those of glutaminase and glucose-6-phosphate dehydrogenase. Dexamethasone had a similar effect except on glucose6-phosphate dehydrogenase. The addition of thyroid hormones to the culture medium raised the activities of glutaminase and hexokinase and reduced that of citrate synthase. The results presented support the suggestion that the effects of insulin, glucocorticoids and thyroid hormones on immune and inflammatory responses could well be mediated through changes in macrophage metabolism.. Journal of Endocrinology (1992) 135, 213–219

scholarly journals Pentose Phosphate Pathway Regulates Tolerogenic Apoptotic Cell Clearance and Immune Tolerance

2022 ◽  
Vol 12 ◽  
Author(s):  
Dan He ◽  
Qiangdongzi Mao ◽  
Jialin Jia ◽  
Zhiyu Wang ◽  
Yu Liu ◽  
...  
Keyword(s):  
Inflammatory Response ◽  
Immune Tolerance ◽  
Lupus Erythematosus ◽  
Pentose Phosphate Pathway ◽  
Apoptotic Cell ◽  
Pentose Phosphate ◽  
Metabolic Reprogramming ◽  
Macrophage Phagocytosis ◽  
Cell Clearance ◽  
Underlying Mechanisms

The efficient removal of apoptotic cells (ACs), a process termed as efferocytosis, is essential for immune homeostasis. While recent work has established an important interplay between efferocytosis and cellular metabolic changing, underlying mechanisms remain poorly known. Here, we discovered that pentose phosphate pathway (PPP) regulates tolerogenic ACs clearance and immune tolerance. ACs decreased levels of PPP-related genes and metabolites in macrophages. AG1, the agonist of PPP, increased the activity of PPP but greatly reduced macrophage phagocytosis of ACs and enhanced the inflammatory response during efferocytosis. miR-323-5p regulated the expression of PPP-related genes and its levels increased during efferocytosis. miR-323-5p inhibitor greatly promoted levels of PPP-related genes, reduced the macrophage phagocytosis of ACs, and increased inflammatory response during efferocytosis, suggesting that miR-323-5p was essential in regulating PPP activity and ACs clearance in macrophages. Correspondingly, the PPP agonist AG1 exacerbated the lupus-like symptoms in the AC-induced systemic lupus erythematosus (SLE) model. Our study reveals that regulating PPP-dependent metabolic reprogramming is critical for tolerogenic ACs phagocytosis and immune tolerance.

Positional information and pattern regulation in hydra: enzyme profiles

Development ◽  
1975 ◽  
Vol 33 (4) ◽  
pp. 853-867
Author(s):  
Najma Zaheer Baquer ◽  
Patricia McLean ◽  
Amata Hornbruch ◽  
L. Wolpert
Keyword(s):  
Pentose Phosphate Pathway ◽  
Citrate Synthase ◽  
Positional Information ◽  
Pentose Phosphate ◽  
Basal Region ◽  
Redox Systems ◽  
Metabolic Pattern ◽  
Alternative Pathways ◽  
Redox States ◽  
Pattern Regulation

Certain key enzymes of alternative pathways of glucose metabolism, of amino acid metabolism and of redox systems have been measured in hydra and this profile compared with mammalian differentiated tissues with a view to locating pathways of specific importance in hydra. There was a marked constant proportionality in the major part of the enzymes investigated, the profile suggested a metabolic pattern geared to utilization of amino acids as a carbon source for biosynthesis and energy production and to the production and conservation of pyruvate. The importance of conversion to ionized forms was noted. The most notable specific proportion changes were the exceptionally low lactate dehydrogenase, malic enzyme and the relatively high citrate synthase. The proximal-distal gradients in hydra were examined and these gradients suggested a switch to a more anaerobic type of metabolism and an elevation of the pentose phosphate pathway as the basal region was approached. Measurements of the formation of 14CO2 from specifically labelled glucose provided additional evidence for the functional activity and polarity of the pentose phosphate pathway in hydra. The effect of oligomycin, which can reverse polarity in hydra, had a significant effect on gradients of enzymes eliminating all except that observed for G6P dehydrogenase. The profile suggested a movement towards a more anaerobic type of metabolism, in keeping with the known biochemical action of this inhibitor. It is suggested that redox states and/or phosphorylation states may be featured in the positional information of cells in hydra.

scholarly journals YvcK of Bacillus subtilis is required for a normal cell shape and for growth on Krebs cycle intermediates and substrates of the pentose phosphate pathway

Microbiology ◽  
2005 ◽  
Vol 151 (11) ◽  
pp. 3777-3791 ◽  
Author(s):  
Boris Görke ◽  
Elodie Foulquier ◽  
Anne Galinier
Keyword(s):  
Bacillus Subtilis ◽  
Pentose Phosphate Pathway ◽  
Carbon Metabolism ◽  
Carbon Sources ◽  
Krebs Cycle ◽  
Normal Growth ◽  
Central Carbon Metabolism ◽  
Pentose Phosphate ◽  
Homologous Protein ◽  
Krebs Cycle Intermediates

The HPr-like protein Crh has so far been detected only in the bacillus group of bacteria. In Bacillus subtilis, its gene is part of an operon composed of six ORFs, three of which exhibit strong similarity to genes of unknown function present in many bacteria. The promoter of the operon was determined and found to be constitutively active. A deletion analysis revealed that gene yvcK, encoded by this operon, is essential for growth on Krebs cycle intermediates and on carbon sources metabolized via the pentose phosphate pathway. In addition, cells lacking YvcK acquired media-dependent filamentous or L-shape-like aberrant morphologies. The presence of high magnesium concentrations restored normal growth and cell morphology. Furthermore, suppressor mutants cured from these growth defects appeared spontaneously with a high frequency. Such suppressing mutations were identified in a transposon mutagenesis screen and found to reside in seven different loci. Two of them mapped in genes of central carbon metabolism, including zwf, which encodes glucose-6-phosphate dehydrogenase and cggR, the product of which regulates the synthesis of glyceraldehyde-3-phosphate dehydrogenase. All these results suggest that YvcK has an important role in carbon metabolism, probably in gluconeogenesis required for the synthesis of cell wall precursor molecules. Interestingly, the Escherichia coli homologous protein, YbhK, can substitute for YvcK in B. subtilis, suggesting that the two proteins have been functionally conserved in these different bacteria.

Respiratory enzyme activities during germination inBrassicaseed lots of differing vigour

1996 ◽  
Vol 6 (4) ◽  
pp. 165-174 ◽  
Author(s):  
Mary Bettey ◽  
W.E. Finch-Savage
Keyword(s):  
Oxygen Consumption ◽  
Pentose Phosphate Pathway ◽  
Sharp Increase ◽  
Artificial Aging ◽  
Pentose Phosphate ◽  
Untreated Seed ◽  
Seed Vigour ◽  
Regulatory Enzymes ◽  
Rate Of Oxygen Consumption ◽  
Glucose 6 Phosphate Dehydrogenase

AbstractThe rate of oxygen consumption by cabbage seeds increased on imbibition and there was a further sharp increase on germination. This was delayed in artificially aged seeds of low vigour. The increases in oxygen consumption reflect the increased oxidation of carbohydrates via respiratory pathways. The activities of key regulatory enzymes of glycolysis and the oxidative pentose phosphate pathway were measured in aged and unaged seed lots of cabbage. Differences in the activities of glucose 6-phosphate dehydrogenase and pyrophosphate:fructose 6-phosphate 1-phosphotransferase were correlated with the rate of germination (T50) in seed lots with large differences in seed vigour induced experimentally by artificial aging. However, the activities of these enzymes could not be used to distinguish between untreated seed lots which had smaller vigour differences apparent only under stress. The enzymes are presumably not controlling and determining seed vigour, but merely reflecting actual seed performance under the current conditions.

Control of superoxide dismutase, catalase and glutathione peroxidase activities in rat lymphoid organs by thyroid hormones

1994 ◽  
Vol 140 (1) ◽  
pp. 73-77 ◽  
Author(s):  
B Pereira ◽  
L F B P Costa Rosa ◽  
D A Safi ◽  
E J H Bechara ◽  
R Curi
Keyword(s):  
Lipid Peroxidation ◽  
Superoxide Dismutase ◽  
Glutathione Peroxidase ◽  
Thyroid Hormones ◽  
Citrate Synthase ◽  
Lipid Peroxide ◽  
Lymphoid Organs ◽  
Mesenteric Lymph Nodes ◽  
Glucose 6 Phosphate Dehydrogenase ◽  
Reducing Equivalents

Abstract This study examined the effect of experimental hyperand hypothyroidism on the superoxide dismutase, catalase and glutathione peroxidase activities of rat lymphoid organs (mesenteric lymph nodes, spleen and thymus) and muscles (soleus and gastrocnemius-white portion) for comparison. The capacity for the generation of reducing equivalents was also investigated: activities of glucose-6-phosphate dehydrogenase (pentose-phosphate pathway) and citrate synthase (Krebs cycle). Hyperthyroidism tended to enhance lipid peroxide content in all tissues. This effect may result from (1) a high capacity for the generation of reducing equivalents in cytosol and mitochondria and (2) a reduced activity of catalase in the lymphoid organs and of glutathione peroxidase in the muscles. The process of lipid peroxidation in these tissues caused by hyperthyroidism was probably slowed down by the augmentation of CuZn- and Mn-superoxide dismutase (Mn-SOD) activities observed under this condition. Hypothyroidism tended to diminish lipid peroxidation and did not affect citrate synthase and glucose-6-phosphate dehydrogenase activities in the lymphoid organs and muscles. Low levels of thyroid hormones tended to diminish Mn-SOD and glutathione peroxidase activities. These findings show that the thyroid hormones might be able to regulate the activities of CuZn- and Mn-SOD, and catalase and glutathione peroxidase in the lymphoid organs and skeletal muscles. Journal of Endocrinology (1994) 140, 73–77

A study of the relationship between seed dormancy and pentose phosphate pathway activity in Avena fatua

1983 ◽  
Vol 61 (3) ◽  
pp. 667-670 ◽  
Author(s):  
E. P. Fuerst ◽  
M. K. Upadhyaya ◽  
G. M. Simpson ◽  
J. M. Naylor ◽  
S. W. Adkins
Keyword(s):  
Seed Dormancy ◽  
Pentose Phosphate Pathway ◽  
Krebs Cycle ◽  
Pure Line ◽  
Pentose Phosphate ◽  
Avena Fatua ◽  
Wild Oats ◽  
Gibberellin Treatment ◽  
The Relationship ◽  
Increased Activity

The hypothesis that loss of seed dormancy is associated with an increased activity of the pentose phosphate pathway (PPP) relative to glycolysis and the Krebs cycle was tested. The PPP activity was monitored by measuring the C6/C1 ratio in embryos excised from incubated caryopses of two genetically pure nondormant (ND) lines and in three dormant (D) lines of Avena fatua L., the wild oat. The C6/C1 ratios of all lines were similar at the commencement of incubation. In the two ND lines the ratio increased steadily prior to and during emergence of the radicle. In the three D lines the ratio increased during the first 24 h and then remained almost constant; there was no germination. When gibberellin treatment was used to overcome dormancy in the D lines, the C6/C1 ratio increased during the first 24 h in two of the lines and continued to increase parallel to germination in a manner similar to normal germination in ND lines. In the third D line, despite loss of dormancy from gibberellin treatment, the ratio did not increase after 24 h. Loss of dormancy during dry storage of seeds of a D-type pure line was accompanied by an increase in the C6/C1 ratio, as measured in freshly imbibed seeds. This indicates a decreased activity of the PPP relative to glycolysis and the Krebs cycle. These findings are contrary to Roberts's hypothesis that loss of dormancy in wild oats is associated with a relative decrease in the C6/C1 ratio.

scholarly journals Regulation of the pentose phosphate cycle Cofactor that controls the inhibition of glucose-6-phosphate dehydrogenase by NADPH in rat liver

1986 ◽  
Vol 239 (3) ◽  
pp. 553-558 ◽  
Author(s):  
M Nogueira ◽  
G Garcia ◽  
C Mejuto ◽  
M Freire
Keyword(s):  
Ion Exchange ◽  
Rat Liver ◽  
Pentose Phosphate Pathway ◽  
Reductase Activity ◽  
Gel Filtration ◽  
Ion Exchange Chromatography ◽  
Exchange Chromatography ◽  
Pentose Phosphate ◽  
Glutathione Reductase Activity ◽  
Glucose 6 Phosphate Dehydrogenase

A cofactor of Mr 10(4), characterized as a polypeptide, was found to co-operate with GSSG to prevent the inhibition of glucose-6-phosphate dehydrogenase by NADPH, in order to ensure the operation of the oxidative phase of the pentose phosphate pathway, in rat liver [Eggleston & Krebs (1974) Biochem. J. 138, 425-435; Rodriguez-Segade, Carrion & Freire (1979) Biochem. Biophys. Res. Commun. 89, 148-154]. This cofactor has now been partially purified by ion-exchange chromatography and molecular gel filtration, and characterized as a protein of Mr 10(5). The lighter cofactor reported previously was apparently the result of proteolytic activity generated during the tissue homogenization. The heavier cofactor was unstable, and its amount increased in livers of rats fed on carbohydrate-rich diet. Since the purified cofactor contained no glutathione reductase activity, the involvement of this enzyme in the deinhibitory mechanism of glucose-6-phosphate dehydrogenase by NADPH should be ruled out.

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