scholarly journals Insulin and the regulation of adipose-tissue acetyl-coenzyme A carboxylase

1973 ◽  
Vol 132 (3) ◽  
pp. 509-517 ◽  
Author(s):  
Andrew P. Halestrap ◽  
Richard M. Denton
Keyword(s):  
Fatty Acyl ◽  
Acetyl Coa Carboxylase ◽  
Fat Cell ◽  
Acetyl Coa ◽  
Carboxylase Activity ◽  
Insulin Effect ◽  
Marked Diminution ◽  
Slow Dissociation ◽  
Acetyl Coenzyme A Carboxylase ◽  
Long Chain

Rat epididymal fat-pads were incubated for 30min with glucose (2mg/ml) in the presence or absence of insulin. A twofold or greater increase in acetyl-CoA carboxylase activity was observed in extracts from insulin-treated tissue provided that assays were performed rapidly after extraction. This effect of insulin was evident whether or not extracts were prepared with albumin, and was not noticeably diminished by the presence of citrate or albumin or both in the assay. Incubation of extracts before assay led to activation of acetyl-CoA carboxylase and a marked diminution in the insulin effect. The enzyme in extracts was very sensitive to reversible inhibition by palmitoyl-CoA even in the presence of albumin (10mg/ml); inhibition persisted on dilution of enzyme and inhibitor. It is suggested that the observed activation of acetyl-CoA carboxylase by insulin may reflect changes in enzyme activity in the fat-cell resulting from the reduction of long-chain fatty-acyl-CoA that occurs in the presence of insulin. Activation of the enzyme with loss of the insulin effect on incubation of the extracts may be due to the slow dissociation of long-chain fatty acyl-CoA from the enzyme.

Expression Profile of Acetyl CoA Carboxylase Beta (ACACB) Gene during the Pre and Post-hatch Period in Chicken

2021 ◽  
Author(s):  
Ch. Shiva Prasad ◽  
R. Vinoo ◽  
R.N. Chatterjee ◽  
M. Muralidhar ◽  
D. Narendranath ◽  
...  
Keyword(s):  
Gene Expression ◽  
Fatty Acid ◽  
Expression Pattern ◽  
Fatty Acyl ◽  
Acid Oxidation ◽  
Acetyl Coa Carboxylase ◽  
Acetyl Coa ◽  
Layer Chicken ◽  
Differential Expression Pattern ◽  
Long Chain

Background: Acetyl-CoA Carboxylase Beta (ACACB) plays a key role in fatty acid oxidation and was known to be involved in production of very-long-chain fatty acid and other compounds needed for proper development. This gene is mainly expressed in the tissues of heart, muscle, liver and colon. It chiefly involved in the production of malonyl-coA, a potent inhibitor of carnitine palmitoyl transferase I (CPT-I) enzyme needed in transport of long-chain fatty acyl-coAs to the mitochondria for β-oxidation.Methods: The present study was conducted to explore the expression pattern of the ACACB gene in breast muscle tissue during pre-hatch embryonic day (ED) 5th to 18th and post-hatch (18th, 22nd and 40th week of age) periods of White leghorn (IWI line) by using Quantitative real-time PCR (qPCR). Then, fold change of ACACB gene expression was calculated.Result: Our study showed that the ACACB gene expression was down-regulated during embryonic stages from ED6 to ED18. The gene expression was also down-regulated during adult stages i.e. on 22nd and 40th week of age. This result indicated that the initial expression of the ACACB gene is required for embryo development and during adult periods, low gene expression leads to the less fat deposition in muscle of layer chicken. Finally, it can be concluded that there was a differential expression pattern of the ACACB gene during the pre-hatch embryonic and post-hatch adult periods to mitigate varied requirements of lipids during different physiological stages in layer chicken.

scholarly journals Role of long-chain fatty acyl-CoA esters in the regulation of metabolism and in cell signalling

1997 ◽  
Vol 323 (1) ◽  
pp. 1-12 ◽  
Author(s):  
Nils Joakim FÆRGEMAN ◽  
Jens KNUDSEN
Keyword(s):  
Binding Proteins ◽  
Feedback Inhibition ◽  
Fatty Acyl ◽  
Acetyl Coa Carboxylase ◽  
Acetyl Coa ◽  
Release Channel ◽  
Δ9 Desaturase ◽  
Chain Acyl ◽  
Long Chain

The intracellular concentration of free unbound acyl-CoA esters is tightly controlled by feedback inhibition of the acyl-CoA synthetase and is buffered by specific acyl-CoA binding proteins. Excessive increases in the concentration are expected to be prevented by conversion into acylcarnitines or by hydrolysis by acyl-CoA hydrolases. Under normal physiological conditions the free cytosolic concentration of acyl-CoA esters will be in the low nanomolar range, and it is unlikely to exceed 200 nM under the most extreme conditions. The fact that acetyl-CoA carboxylase is active during fatty acid synthesis (Ki for acyl-CoA is 5 nM) indicates strongly that the free cytosolic acyl-CoA concentration is below 5 nM under these conditions. Only a limited number of the reported experiments on the effects of acyl-CoA on cellular functions and enzymes have been carried out at low physiological concentrations in the presence of the appropriate acyl-CoA-buffering binding proteins. Re-evaluation of many of the reported effects is therefore urgently required. However, the observations that the ryanodine-senstitive Ca2+-release channel is regulated by long-chain acyl-CoA esters in the presence of a molar excess of acyl-CoA binding protein and that acetyl-CoA carboxylase, the AMP kinase kinase and the Escherichia coli transcription factor FadR are affected by low nanomolar concentrations of acyl-CoA indicate that long-chain acyl-CoA esters can act as regulatory molecules in vivo. This view is further supported by the observation that fatty acids do not repress expression of acetyl-CoA carboxylase or Δ9-desaturase in yeast deficient in acyl-CoA synthetase.

scholarly journals Critical phosphorylation sites for acetyl-CoA carboxylase activity.

1994 ◽  
Vol 269 (35) ◽  
pp. 22162-22168 ◽  
Author(s):  
J. Ha ◽  
S. Daniel ◽  
S.S. Broyles ◽  
K.H. Kim
Keyword(s):  
Phosphorylation Sites ◽  
Acetyl Coa Carboxylase ◽  
Acetyl Coa ◽  
Carboxylase Activity

Relative Activities of Acetyl-CoA Carboxylase and Fatty Acid Synthetase in Chick Liver: Effects of Dietary Fat

1973 ◽  
Vol 51 (7) ◽  
pp. 1029-1033 ◽  
Author(s):  
Gregory I. Liou ◽  
W. E. Donaldson
Keyword(s):  
Fatty Acid ◽  
Corn Oil ◽  
Fatty Acid Synthetase ◽  
Basal Diet ◽  
Acetyl Coa Carboxylase ◽  
Acetyl Coa ◽  
Carboxylase Activity ◽  
Cytosol Fraction ◽  
Activity Concentrations

The specific activities of acetyl-CoA carboxylase and fatty acid synthetase were measured in the cytosol fraction of livers from chicks fed various levels of corn oil, cottonseed oil, corn-oil free fatty acids, or crude (79%) oleic acid. Activities of both enzymes were depressed by the addition of fat to a fat-free basal diet. The ratios of synthetase to carboxylase activity were greater than unity when up to 4% fat was fed, but less than unity when 8% or higher levels of fat were fed. The depressions of the activities of these enzymes appeared to be unrelated to the dietary level of linoleate. In in vitro experiments, 2 μM concentrations of palmityl-CoA or oleoyl-CoA depressed acetyl-CoA carboxylase activity. Concentrations of 20 μM of these acyl-CoA esters did not affect the activity of fatty acid synthetase.

scholarly journals Growth-hormone-prolactin interactions in the regulation of mammary and adipose-tissue acetyl-CoA carboxylase activity and gene expression in lactating rats

1992 ◽  
Vol 285 (2) ◽  
pp. 469-475 ◽  
Author(s):  
M C Barber ◽  
M T Travers ◽  
E Finley ◽  
D J Flint ◽  
R G Vernon
Keyword(s):  
Adipose Tissue ◽  
Mammary Gland ◽  
Serum Prolactin ◽  
Acetyl Coa Carboxylase ◽  
Acetyl Coa ◽  
Carboxylase Activity ◽  
Total Enzyme Activity ◽  
Mrna Concentration ◽  
Total Enzyme ◽  
Activation Status

The factors and mechanisms responsible for the reciprocal changes in lipogenesis in rat mammary gland and adipose tissue during the lactation cycle have been investigated. Lactation decreased the activation status and mRNA concentration of acetyl-CoA carboxylase in adipose tissue. Litter removal decreased the mRNA concentration of acetyl-CoA carboxylase in the mammary gland and increased the enzyme's mRNA concentration and activation status in adipose tissue. Lowering serum prolactin concentration in lactating rats decreased the amount of mammary acetyl-CoA carboxylase mRNA and increased that of adipose tissue, and increased the activation status of the enzyme in adipose tissue. Decreasing serum growth hormone (GH) alone had little effect on acetyl-CoA carboxylase in lactating rats, although it did lower pup growth rate and serum concentration of insulin-like growth factor-I. Lowering serum GH concentration exacerbated the effects of decreasing serum prolactin on mammary-gland (but not adipose-tissue) acetyl-CoA carboxylase mRNA and further increased the rise in activation status of the adipose-tissue enzyme induced by decreasing serum prolactin. Changes in acetyl-CoA carboxylase mRNA in both mammary and adipose tissue were paralleled by changes in total enzyme activity except after litter removal, when there was a disproportionately large decrease in total enzyme activity of the mammary gland. Thus prolactin has a major and GH a minor role in the regulation of acetyl-CoA carboxylase activity during lactation. Changes in mammary activity in response to prolactin and GH are primarily due to alterations in gene transcription, whereas adaptation in adipose tissue involves both changes in gene transcription and activation status.

scholarly journals Association between Hydrogen Peroxide-Dependent Byproducts of Ascorbic Acid and Increased Hepatic Acetyl-CoA Carboxylase Activity

2005 ◽  
Vol 51 (8) ◽  
pp. 1462-1471 ◽  
Author(s):  
Laurent Knafo ◽  
Philippe Chessex ◽  
Thérèse Rouleau ◽  
Jean-Claude Lavoie
Keyword(s):  
Ascorbic Acid ◽  
Lipid Metabolism ◽  
Guinea Pig ◽  
Dehydroascorbic Acid ◽  
Biologically Active ◽  
Urinary Concentration ◽  
Acetyl Coa Carboxylase ◽  
High Concentration ◽  
Acetyl Coa ◽  
Carboxylase Activity

Abstract Background: Parenteral multivitamin preparation (MVP) induces fatty liver in neonatal guinea pig pups; this is prevented by photoprotection. Photo-excited riboflavin present in MVP generates H2O2 and molecules with masses of 136 and 208. We hypothesized that H2O2 initiates the peroxidation of ascorbic acid (AA), producing biologically active byproducts affecting hepatic lipid metabolism. Methods: Mass spectrometry (MS) documented the participation of H2O2 and photo-excited riboflavin (Ribo) in the formation of AA byproducts. Sixteen 3-day-old guinea pig pups received an intravenous solution (50 g/L dextrose + 4.5 g/L NaCl + 1 kIU/L heparin) at 240 mL · kg−1 · day−1, enriched with control or test mixtures, for 4 days. The control mixture was photo-protected AA + Ribo (without byproducts or H2O2), and the test mixture was AA + Ribo treated to generate AA byproducts without H2O2. Hepatic acetyl-CoA carboxylase (ACC) activity was determined after 4 days. Fourth-day urine samples were analyzed by MS. Data were treated by ANOVA (α = 0.05). Results: H2O2 did not influence the classic degradation of AA, as the generation of 2,3-diketogulonic acid was not affected. In contrast, the formation of molecules with masses of 136 and 208 was H2O2 and time dependent. ACC activity was higher (P <0.01) in animals receiving high concentration of these molecules; its hepatic activation correlated (P <0.01) with the urinary concentration of molecule-208. Conclusions: H2O2 at concentrations found in the clinical setting of total parenteral nutrition induce the transformation of dehydroascorbic acid into compounds that have the potential to affect lipid metabolism. These molecules have peroxide and aldehyde functions.

scholarly journals Both insulin and epidermal growth factor stimulate lipogenesis and acetyl-CoA carboxylase activity in isolated adipocytes. Importance of homogenization procedure in avoiding artefacts in acetyl-CoA carboxylase assay

1986 ◽  
Vol 234 (2) ◽  
pp. 279-284 ◽  
Author(s):  
T A Haystead ◽  
D G Hardie
Keyword(s):  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Maximal Effect ◽  
Acetyl Coa Carboxylase ◽  
Homogenization Procedure ◽  
Acetyl Coa ◽  
Carboxylase Activity ◽  
Epidermal Growth ◽  
Isolated Adipocytes ◽  
Significant Interference

Epidermal growth factor (EGF) stimulates lipogenesis by 3-4-fold in isolated adipocytes, with a half-maximal effect at 10 nM-EGF. In the same batches of cells insulin stimulated lipogenesis by 15-fold. Freezing and prolonged homogenization of adipocytes results in release of large quantities of pyruvate carboxylase from broken mitochondria, and sufficient pyruvate can be carried through into assays for this enzyme to cause significant interference with assays of acetyl-CoA carboxylase in crude adipocyte extracts. This may account for the high amount of citrate-independent acetyl-CoA carboxylase activity reported to be present in adipocyte extracts in some previous publications. This problem may be eliminated by homogenizing very briefly without freezing. By using the modified homogenization procedure, EGF treatment of adipocytes was shown to produce an effect on acetyl-CoA carboxylase activity almost identical with that of insulin. Both messengers increase Vmax. without significant effect on the Ka for the allosteric activator, citrate.

scholarly journals Insulin activation of lipogenesis in isolated mammary acini from lactating rats fed on a high-fat diet. Evidence that acetyl-CoA carboxylase is a site of action

1987 ◽  
Vol 242 (3) ◽  
pp. 905-911 ◽  
Author(s):  
M R Munday ◽  
D H Williamson
Keyword(s):  
Glucose Uptake ◽  
High Fat Diet ◽  
Acetyl Coa Carboxylase ◽  
High Fat ◽  
Acetyl Coa ◽  
Carboxylase Activity ◽  
Glucose Incorporation ◽  
Site Of Action ◽  
A Site

Feeding lactating rats on high-fat cheese crackers in addition to laboratory chow increased the dietary intake of fat from 2 to 20% of the total weight of food eaten and decreased mammary-gland lipogenesis in vivo by approx. 50%. This lipogenic inhibition was also observed in isolated mammary acini, where it was accompanied by decreased glucose uptake. These inhibitions were completely reversed by incubation with insulin. Insulin had no effect on the rate of glucose transport into acini, nor on pyruvate dehydrogenase activity as estimated by the accumulation of pyruvate and lactate, suggesting that these are not the sites of lipogenic inhibition. Insulin stimulated the incorporation of [1-14C]acetate into lipid in acini from high-fat-fed rats. In the presence of alpha-cyanohydroxycinnamate, a potent inhibitor of mitochondrial pyruvate transport, and with glucose as the sole substrate, neither [1-14C]glucose incorporation into lipid nor glucose uptake were stimulated by insulin. Insulin did stimulate the incorporation of [1-14C]acetate into lipid in the presence of alpha-cyanohydroxycinnamate, and this was accompanied by an increase in glucose uptake by the acini. This indicated that increased glucose uptake was secondary to the stimulation of lipogenesis by insulin, which therefore must occur via activation of a step in the pathway distal to mitochondrial pyruvate transport. Insulin stimulated acetyl-CoA carboxylase activity measured in crude extracts of acini from high-fat-fed rats, restoring it to values close to those of chow-fed controls. The effects of insulin on acetyl-CoA carboxylase activity and lipogenesis were not antagonized by adrenaline or dibutyryl cyclic AMP.

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