scholarly journals Changes in the activity of citrate lyase, malic enzyme and acetyl-CoA synthetase in rat liver after short-term and long-term feeding with ethanol

1973 ◽  
Vol 29 (2) ◽  
pp. 307-316 ◽  
Author(s):  
E. Fellenius ◽  
U. Nisbeth ◽  
L. Pilström ◽  
K.-H. Kiessling

1. The effect of short-term and long-term feeding (0–80 d) with a liquid diet containing ethanol on the activity of rat hepatic enzymes related to lipogenesis has been evaluated. Carbohydrates were isoenergetically substituted for ethanol in the control animals.2. The maximum concentration of triglycerides in the livers was reached after about 30 d, when it was almost three times as high as in the control animals. The activity of malic enzyme (EC 1·1·1·40) and ATP citrate lyase (EC 4·1·3·8) decreased significantly in the ethanol group, compared with the control rats, within 10 d and remained low during the rest of the experiment (80 d). After 20 d, the acetyl-CoA synthetase (EC 6·2·1·1) activity increased significantly in the livers of the ethanol-fed rats but fell subsequently to values similar to those in the livers of the control rats. Thus, despite a pronounced increase in the amount of triglyceride in the livers of rats on a liquid diet containing ethanol, there was a dramatic decrease in the activity of the enzymes (malic enzyme and citrate lyase) involved in lipogenesis.3. The almost unchanged activity of acetyl-CoA synthetase shows that the utilization of acetate, produced when ethanol is oxidized, is not stimulated by long-term feeding with ethanol. The involvement of citrate lyase in various postulated shuttles for the transport of reducing equivalents across the mitochondrial membrane and the role of malic enzyme in the microsomal ethanol-oxidizing system are discussed.

2002 ◽  
Vol 283 (4) ◽  
pp. H1379-H1386 ◽  
Author(s):  
Myriame Poirier ◽  
Geneviève Vincent ◽  
Aneta E. Reszko ◽  
Bertrand Bouchard ◽  
Joanne K. Kelleher ◽  
...  

Little is known about the sources of cytosolic acetyl-CoA used for the synthesis of malonyl-CoA, a key regulator of fatty acid oxidation in the heart. We tested the hypothesis that citrate provides acetyl-CoA for malonyl-CoA synthesis after its mitochondrial efflux and cleavage by cytosolic ATP-citrate lyase. We expanded on a previous study where we characterized citrate release from perfused rat hearts (Vincent G, Comte B, Poirier M, and Des Rosiers C. Citrate release by perfused rat hearts: a window on mitochondrial cataplerosis. Am J Physiol Endocrinol Metab 278: E846–E856, 2000). In the present study, we show that citrate release rates, ranging from 6 to 22 nmol/min, can support a net increase in malonyl-CoA concentrations induced by changes in substrate supply, at most 0.7 nmol/min. In experiments with [U-13C](lactate + pyruvate) and [1-13C]oleate, we show that the acetyl moiety of malonyl-CoA is derived from both pyruvate and long-chain fatty acids. This 13C-labeling of malonyl-CoA occurred without any changes in its concentration. Hydroxycitrate, an inhibitor of ATP-citrate lyase, prevents increases in malonyl-CoA concentrations and decreases its labeling from [U-13C](lactate + pyruvate). Our data support at least a partial role of citrate in the transfer from the mitochondria to cytosol of acetyl units for malonyl-CoA synthesis. In addition, they provide a dynamic picture of malonyl-CoA metabolism: even when the malonyl-CoA concentration remains constant, there appears to be a constant need to supply acetyl-CoA from various carbon sources, both carbohydrates and lipids, for malonyl-CoA synthesis.


1970 ◽  
Vol 118 (1) ◽  
pp. 155-162 ◽  
Author(s):  
Elizabeth A. Lockwood ◽  
E. Bailey ◽  
C. B. Taylor

1. Changes in the activities of acetyl-CoA carboxylase (EC 6.4.1.2), phosphofructokinase (EC 2.7.1.11), aldolase (EC 4.1.2.13), extramitochondrial aconitate hydratase (EC 4.2.1.3) and NADP-dependent isocitrate dehydrogenase (EC 1.1.1.42) have been measured in the livers of developing rats from late foetal life to maturity. 2. The effect of altering the weaning time on some enzymes associated with lipogenesis has been studied. Weaning rats at 15 days of age instead of 21 days results in an immediate increase in the activity of `malic' enzyme (EC 1.1.1.40) whereas the activities of glucose 6-phosphate dehydrogenase (EC 1.1.1.49) and ATP citrate lyase (EC 4.1.3.8) did not increase until 4–5 days and acetyl-CoA carboxylase 2–3 days after early weaning. Weaning rats on to an artificial-milk diet led to complete repression of the rise in activity of hepatic enzymes associated with lipogenesis normally found on weaning, except for `malic' enzyme, which increased in activity after 20 days of age. 3. The effect of intraperitoneal injections of glucagon, cortisol, growth hormone and thyroxine on the same hepatic enzymes has been investigated. Only thyroxine had any effect on enzyme activities and caused a 20-fold increase in `malic' enzyme activity and a twofold increase in ATP citrate lyase activity. 4. The activities of hepatic glucose 6-phosphate dehydrogenase and `malic' enzyme are higher in adult female than in adult male rats and it has been shown that this sex difference in enzyme activities is due to both male and female sex hormones. 5. Hepatic malate, citrate, pyruvate, glucose 6-phosphate and phosphoenolpyruvate concentrations have been measured throughout development. 6. The results are discussed in relation to the dietary and hormonal control of hepatic enzyme activities during development.


2010 ◽  
Vol 61 (3) ◽  
pp. 463-468 ◽  
Author(s):  
Aidil Abdul Hamid ◽  
Noor Fatmawati Mokhtar ◽  
Ekhlass M. Taha ◽  
Othman Omar ◽  
Wan Mohtar Wan Yusoff

Plants ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 350 ◽  
Author(s):  
Lingxia Guo ◽  
Yongzhong Liu ◽  
Lijuan Luo ◽  
Syed Bilal Hussain ◽  
Yingxin Bai ◽  
...  

Citric acid metabolism is considered to be the central cellular process of metabolite conversions. ATP-citrate lyase (ACL) and cytosolic aconitase (cyt-ACO) are the two citrate-degrading enzymes that decide the carbon flux towards different metabolite biosynthesis pathways. However, the correlation of their activities with metabolite concentrations in citrus fruits is still unclear. Here, the concentrations of soluble sugars, organic acids, acetyl-CoA, flavonoids, carotenoids, and γ-aminobutyric acid, as well as the activities of ACL, cyt-ACO, acetyl-CoA C-acetyltransferase, and acetyl-CoA carboxylase, were compared among the fruits of six citrus cultivars during fruit development and ripening. The results showed that the correlation between citrate concentration and cyt-ACO or ACL activity varied greatly among cultivars, while the activities of cyt-ACO and ACL had a significantly negative correlation (r = −0.4431). Moreover, ACL overexpression and RNA interference in the Citrus callus indicated that increasing and decreasing the ACL activity could reduce and induce cyt-ACO activity, respectively. In addition, significant correlation was only observed between the ACL activity and the concentration of acetyl-CoA (r = 0.4333). Taken together, the present study suggested that ACL and cyt-ACO synergistically control the citrate fate for the biosynthesis of other metabolites, but they are not the key determinants for the accumulation of citrate, as well as other metabolites in citrus fruits.


2021 ◽  
Vol 12 ◽  
Author(s):  
Monica Dominguez ◽  
Bernhard Brüne ◽  
Dmitry Namgaladze

Studies over the past decade have revealed that metabolism profoundly influences immune responses. In particular, metabolism causes epigenetic regulation of gene expression, as a growing number of metabolic intermediates are substrates for histone post-translational modifications altering chromatin structure. One of these substrates is acetyl-coenzyme A (CoA), which donates an acetyl group for histone acetylation. Cytosolic acetyl-CoA is also a critical substrate for de novo synthesis of fatty acids and sterols necessary for rapid cellular growth. One of the main enzymes catalyzing cytosolic acetyl-CoA formation is ATP-citrate lyase (ACLY). In addition to its classical function in the provision of acetyl-CoA for de novo lipogenesis, ACLY contributes to epigenetic regulation through histone acetylation, which is increasingly appreciated. In this review we explore the current knowledge of ACLY and acetyl-CoA in mediating innate and adaptive immune responses. We focus on the role of ACLY in supporting de novo lipogenesis in immune cells as well as on its impact on epigenetic alterations. Moreover, we summarize alternative sources of acetyl-CoA and their contribution to metabolic and epigenetic regulation in cells of the immune system.


2016 ◽  
Vol 1 (1) ◽  
Author(s):  
Dr. Kamlesh Kumar Shukla

FIIs are companies registered outside India. In the past four years there has been more than $41 trillion worth of FII funds invested in India. This has been one of the major reasons on the bull market witnessing unprecedented growth with the BSE Sensex rising 221% in absolute terms in this span. The present downfall of the market too is influenced as these FIIs are taking out some of their invested money. Though there is a lot of value in this market and fundamentally there is a lot of upside in it. For long-term value investors, there’s little because for worry but short term traders are adversely getting affected by the role of FIIs are playing at the present. Investors should not panic and should remain invested in sectors where underlying earnings growth has little to do with financial markets or global economy.


1997 ◽  
Vol 35 (1) ◽  
pp. 1-7 ◽  
Author(s):  
Brian De Vries

This article introduces a volume devoted to the examination of later-life bereavement: an analysis of variation in cause, course, and consequence. Six articles address and represent this variation and comprise this volume: 1) Prigerson et al. present case histories of the traumatic grief of spouses; 2) Hays et al. highlight the bereavement experiences of siblings in contrast to those spouses and friends; 3) Moss et al. address the role of gender in middle-aged children's responses to parent death; 4) Bower focuses on the language adopted by these adult children in accepting the death of a parent; 5) de Vries et al. explore the long-term, longitudinal effects on the psychological and somatic functioning of parents following the death of an adult child; and 6) Fry presents the short-term and longitudinal reactions of grandparents to the death of a grandchild. A concluding article is offered by de Vries stressing both the unique and common features of these varied bereavement experiences touching on some of the empirical issues and suggesting potential implications and applications.


2021 ◽  
Vol 13 (9) ◽  
pp. 5024
Author(s):  
 Vítor Manuel de Sousa Gabriel ◽  
María Mar Miralles-Quirós ◽  
José Luis Miralles-Quirós

This paper analyses the links established between environmental indices and the oil price adopting a double perspective, long-term and short-term relationships. For that purpose, we employ the Bounds Test and bivariate conditional heteroscedasticity models. In the long run, the pattern of behaviour of environmental indices clearly differed from that of the oil prices, and it was not possible to identify cointegrating vectors. In the short-term, it was possible to conclude that, in contemporaneous terms, the variables studied tended to follow similar paths. When the lag of the oil price variable was considered, the impacts produced on the stock market sectors were partially of a negative nature, which allows us to suppose that this variable plays the role of a risk factor for environmental investment.


Author(s):  
Kenneth Verstraete ◽  
Koen H. G. Verschueren ◽  
Ann Dansercoer ◽  
Savvas N. Savvides

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