Improved methods for the assay and activation of 3-hydroxy-3-methylglutaryl coenzyme A reductase.

Philipp, B. W.; Shapiro, David J.

doi:10.1016/s0022-2275(20)40580-2

Cited by 137 publications

(9 citation statements)

References 17 publications

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“…Very low density lipoprotein cholesterol (VLDL-C) and low density lipoprotein cholesterol (LDL-C) fractions were calculated as VLDL-C = TG/5 and LDL-C = total cholesterol -(HDL-C + VLDL-C), respectively. The activity of hydroxy 3-methylglutaryl-coenzyme A (HMG CoA) reductase in the liver & kidney was assayed by the method of Philipp and Shapiro (1970). The ratio between HMG CoA and mevalonate in the liver was taken as an index of the activity of HMG CoA reductase.…”

Section: Methodsmentioning

confidence: 99%

Effect of Tetrahydrocurcumin on Lipid Profiles in Streptozotocin–nicotinamide Induced Type 2 Diabetes Mellitus

Murugan¹

2021

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Hyperlipidemia is one of the major risk factors of cardiovascular complication in diabetes. A study was undertaken to evaluate the antihyperlipidemic activity of tetrahydrocurcumin (THC). Oral administration of THC (80mg/ kg bodyweight) to streptozotocin-nicotinamide induced diabetic rats for 45 days, significantly reduced the elevated serum very low density lipoprotein (VLDL) and low density lipoprotein (LDL) – cholesterol levels and significantly increased the serum high-density lipoprotein (HDL)-cholesterol. THC showed a better effect when compared with curcumin. Results of the present study indicate that THC showed antihyperlipidemic effect in addition to its antidiabetic effect in type 2 diabetic rats

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Section: Methodsmentioning

confidence: 99%

Effect of Tetrahydrocurcumin on Lipid Profiles in Streptozotocin–nicotinamide Induced Type 2 Diabetes Mellitus

Murugan¹

2021

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“…[16,17]. HMG-CoA reductase was determined by measuring the conversion of ['4C]HMG-CoA into mevalonic acid as described by Philipp & Shapiro [18].…”

Section: Methodsmentioning

confidence: 99%

Short- and long-term effects of biliary drainage on hepatic cholesterol metabolism in the rat

Smit

Temmerman

Havinga

et al. 1990

Biochemical Journal

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The present study concerns short- and long-term effects of interruption of the enterohepatic circulation (EHC) on hepatic cholesterol metabolism and biliary secretion in rats. For this purpose, we employed a technique that allows reversible interruption of the EHC, during normal feeding conditions, and excludes effects of anaesthesia and surgical trauma. [3H]Cholesteryl oleate-labelled human low-density lipoprotein (LDL) was injected intravenously in rats with (1) chronically (8 days) interrupted EHC, (2) interrupted EHC at the time of LDL injection and (3) intact EHC. During the first 3 h after interruption of the EHC, bile flow decreased to 50% and biliary bile acid, phospholipid and cholesterol secretion to 5%, 11% and 19% of their initial values respectively. After 8 days of bile diversion, biliary cholesterol output and bile flow were at that same level, but bile acid output was increased 2-3-fold and phospholipid output was about 2 times lower. The total amount of cholesterol in the liver decreased after interruption of the EHC, which was mainly due to a decrease in the amount of cholesteryl ester. Plasma disappearance of LDL was not affected by interruption of the EHC. Biliary secretion of LDL-derived radioactivity occurred 2-4 times faster in chronically interrupted rats as compared with the excretion immediately after interruption of the EHC. Radioactivity was mainly in the form of bile acids under both conditions. This study demonstrates the very rapid changes that occur in cholesterol metabolism and biliary lipid composition after interruption of the EHC. These changes must be taken into account in studies concerning hepatic metabolism of lipoprotein cholesterol and subsequent secretion into bile.

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“…To verify that all of the reductase was in the active form after the differential centrifugation of the samples, each fraction was incubated with potato acid phosphatase for 2 h at 37°C as described (31). After the incubation, the HMG-CoA reductase activity was then measured as previously indicated.…”

Section: Differential Centrifugationmentioning

confidence: 99%

3-Hydroxy-3-methylglutaryl coenzyme A reductase localization in rat liver peroxisomes and microsomes of control and cholestyramine-treated animals: quantitative biochemical and immunoelectron microscopical analyses.

Keller¹,

Pazirandeh²,

Krisans³

1986

The Journal of Cell Biology

141

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Abstract. 3-Hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase, a key regulatory enzyme involved in cholesterol biosynthesis, has recently been reported to be present in rat liver peroxisomes (Keller, G. A., M. C. Barton, D. J. Shapiro, and S. J. Singer, 1985, Proc. Natl. Acad. Sci. USA, 82:770-774). Immunoelectron labeling of ultrathin frozen sections of normal liver, using two monoclonal antibodies to purified rat liver microsomal HMG-CoA reductase, indicated that the enzyme is present in the matrix of peroxisomes. This study is a quantitative biochemical and immunoelectron microscopical analysis of HMGCoA reductase in rat liver peroxisomes and microsomes of normal and cholestyramine-treated animals. Cholestyramine treatment produced a six-to sevenfold increase in the specific activity of peroxisomal HMGCoA reductase, whereas the microsomal HMG-CoA reductase specific activity increased by about twofold. Using a computer program that calculates optimal linear combinations of marker enzymes, it was determined that between 20 and 30% of the total reductase activity was located in the peroxisomes of cholestyramine-treated animals. Less than 5 % of the reductase activity was present in peroxisomes under control conditions. Quantitation of the immunoelectron microscopical data was in excellent agreement with the biochemical results. After cholestymmine treatment there was an eightfold increase in the density of gold particles per peroxisome, and we estimate about a threefold increase in the labeling of the ER.T HE key regulatory enzyme of cholesterol, dolichol, and isopentenyl adenosine biosynthesis, 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) 1 reductase, is a 97-kD transmembrane glycoprotein that was believed until recently to reside exclusively in the endoplasmic reticulum (ER) of mammalian cells (7,8, 27,28). However, a recent publication showed that the enzyme in liver cells is present not only in the ER but also within peroxisomes (18). Immunoelectron labeling of ultrathin frozen sections of normal liver, using two monoclonal antibodies to purified rat liver microsomal HMG-CoA reductase, indicated that the enzyme is concentrated in the matrix of peroxisomes.This study was designed to determine what percentage of the total liver HMG-CoA reductase activity is attributable to the peroxisomal enzyme and to determine if the peroxisomal and the ER enzymes are dependently or independently regulated. Normal rat livers and livers obtained from animals in which the total HMG-CoA reductase activity was increased 1. Abbreviations used in this paper: ER, endoplasmic reticulum; HMGCoA, 3-hydroxy-3-methylglutaryl coenzyme A.by cholestyramine treatment were fractionated by differential and density gradient centrifugation.Two completely independent analyses of the fractions were performed: (a) immunoelectron microscopy with quantitation of the antigenic sites of HMG-CoA reductase; and (b) quantitative enzyme activity measurements of the subcellular fractions with computer-assisted analyses. Materials and Methods Anim...

show abstract

Improved methods for the assay and activation of 3-hydroxy-3-methylglutaryl coenzyme A reductase.

Cited by 137 publications

References 17 publications

Effect of Tetrahydrocurcumin on Lipid Profiles in Streptozotocin–nicotinamide Induced Type 2 Diabetes Mellitus

Effect of Tetrahydrocurcumin on Lipid Profiles in Streptozotocin–nicotinamide Induced Type 2 Diabetes Mellitus

Short- and long-term effects of biliary drainage on hepatic cholesterol metabolism in the rat

3-Hydroxy-3-methylglutaryl coenzyme A reductase localization in rat liver peroxisomes and microsomes of control and cholestyramine-treated animals: quantitative biochemical and immunoelectron microscopical analyses.

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