scholarly journals Activity of 3-hydroxy-3-methylglutaryl-coenzyme A reductase in brains of adult and 7-day-old rats

1976 ◽  
Vol 154 (2) ◽  
pp. 559-560 ◽  
Author(s):  
M M. Sudjic ◽  
R Booth
Keyword(s):  
Rat Brain ◽  
Coenzyme A ◽  
Reductase Activity ◽  
Cholesterol Biosynthesis ◽  
Adult Brain ◽  
Adult Rat ◽  
Adult Rat Brain ◽  
Old Rats ◽  
Coa Reductase ◽  
Coenzyme A Reductase

Rat brain contains 3-hydroxy-3-methylglutaryl-CoA reductase activity, but this enzyme is far more active in 7-day-old brain than in adult brain. This difference may partly explain why cholesterol biosynthesis is more rapid in growing than in adult rat brain.

scholarly journals Pattern of chondroitin sulfate proteoglycan expression after ablation of the sensorimotor cortex of the neonatal and adult rat brain

2008 ◽  
Vol 60 (4) ◽  
pp. 581-591
Author(s):  
Sanja Dacic ◽  
Sanja Pekovic ◽  
Maja Stojiljkovic ◽  
Irena Lavrnja ◽  
Danijela Stojkov ◽  
...  
Keyword(s):  
Chondroitin Sulfate ◽  
Rat Brain ◽  
Sensorimotor Cortex ◽  
Immunohistochemical Analysis ◽  
Recovery Process ◽  
Adult Brain ◽  
Sulfate Proteoglycan ◽  
Adult Rats ◽  
Adult Rat ◽  
Adult Rat Brain

The central nervous system has a limited capacity for self-repair after damage. However, the neonatal brain has agreater capacity for recovery than the adult brain. These differences in the regenerative capability depend on local environmental factors and the maturational stage of growing axons. Among molecules which have both growth-promoting and growth-inhibiting activities is the heterogeneous class of chondroitin sulfate proteoglycans (CSPGs). In this paper, we investigated the chondroitin-4 and chondroitin-6 sulfate proteoglycan expression profile after left sensorimotor cortex ablation of the neonatal and adult rat brain. Immunohistochemical analysis revealed that compared to the normal uninjured cortex, lesion provoked up regulation of CSPGs showing a different pattern of expression in the neonatal vs. the adult brain. Punctuate and membrane-bound labeling was predominate after neonatal lesion, where as heavy deposition of staining in the extracellular matrix was observed after adult lesion. Heavy deposition of CSPG immunoreactivity around the lesionsite in adult rats, in contrast to a less CSPG-rich environment in neonatal rats, indicated that enhancement of the recovery process after neonatal injury is due to amore permissive environment.

scholarly journals A new method for assaying rat liver microsomal 3-hydroxy-3-methylglutaryl-coenzyme A reductase activity and its application in a study of the effect of dietary cholesterol on this effect of dietary cholesterol on this enzyme

1977 ◽  
Vol 164 (3) ◽  
pp. 501-508 ◽  
Author(s):  
Y A Baqir ◽  
R Booth
Keyword(s):  
Rat Liver ◽  
Cholesterol Ester ◽  
Time Course ◽  
Coenzyme A ◽  
Reductase Activity ◽  
Dietary Cholesterol ◽  
New Method ◽  
Coa Reductase ◽  
Microsomal Cholesterol ◽  
Coenzyme A Reductase

A new method suitable for measuring rat liver 3-hydroxy-3-methylglutaryl-CoA reductase activity is described and its advantages over methods previously available are discussed. An accurate time course was measured for the inhibition of liver microsomal 3-hydroxy-3-methylglutaryl-CoA reductase activity by dietary cholesterol; this enzyme was affected 1 1/4 h after the rats began to consume a cholesterol-rich diet. In this experiment there was no correlation between concentrations of microsomal cholesterol ester and the activity of 3-hydroxy-3-methylglutary-CoA reductase.

scholarly journals Effect of phenylalanine on protein synthesis in the developing rat brain

1970 ◽  
Vol 117 (2) ◽  
pp. 325-331 ◽  
Author(s):  
H. C. Agrawal ◽  
A. H. Bone ◽  
A. N. Davison
Keyword(s):  
Amino Acids ◽  
Rat Brain ◽  
Free Amino ◽  
Myelin Proteins ◽  
Free Amino Acid Pool ◽  
Adult Rat ◽  
Adult Rat Brain ◽  
Old Rats ◽  
Developing Rat ◽  
The Brain

1. Inhibition of the rate of incorporation of [35S]methionine into protein by phenylalanine was more effective in 18-day-old than in 8-day-old or adult rat brain. 2. Among the subcellular fractions incorporation of [35S]methionine into myelin proteins was most inhibited in 18-day-old rat brain. 3. Transport of [35S]methionine and [14C]leucine into the brain acid-soluble pool was significantly decreased in 18-day-old rats by phenylalanine (2mg/g body wt.). The decrease of the two amino acids in the acid-soluble pool equalled the inhibition of their rate of incorporation into the protein. 4. Under identical conditions, entry of [14C]glycine into the brain acid-soluble pool and incorporation into protein and uptake of [14C]acetate into lipid was not affected by phenylalanine. 5. It is proposed that decreased myelin synthesis seen in hyperphenylalaninaemia or phenylketonuria may be due to alteration of the free amino acid pool in the brain during the vulnerable period of brain development. Amyelination may be one of many causes of mental retardation seen in phenylketonuria.

scholarly journals 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.

1986 ◽  
Vol 103 (3) ◽  
pp. 875-886 ◽  
Author(s):  
G A Keller ◽  
M Pazirandeh ◽  
S Krisans
Keyword(s):  
Rat Liver ◽  
Coenzyme A ◽  
Specific Activity ◽  
Reductase Activity ◽  
Cholesterol Biosynthesis ◽  
Normal Liver ◽  
Hmg Coa Reductase ◽  
The Matrix ◽  
Coa Reductase ◽  
Liver Peroxisomes

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 HMG-CoA 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 HMG-CoA 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 cholestyramine 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.

3-Hydroxy-3-methylglutaryl coenzyme A reductase activity in beef adrenal cortex

1978 ◽  
Vol 56 (10) ◽  
pp. 958-962 ◽  
Author(s):  
B. Preiss ◽  
L. Tan ◽  
J.-G. Lehoux
Keyword(s):  
Adrenal Cortex ◽  
Sucrose Gradient ◽  
Microsomal Fraction ◽  
Coenzyme A ◽  
Reductase Activity ◽  
Zona Glomerulosa ◽  
Zona Fasciculata ◽  
Hmg Coa Reductase ◽  
Coa Reductase ◽  
Coenzyme A Reductase

3-Hydroxy-3-methylglutaryl coenzyme A reductase (HMG-CoA reductase) activity (mevalonate:NADP+ oxidoreductase (CoA-acylating) EC 1.1.1.34) was demonstrated in beef adrenal cortex. Most of the HMG-CoA reductase activity is in the microsomal fraction while a small percentage of the activity is associated with the mitochondria, Mitochondria purified on a linear sucrose gradient are enriched in HMG-CoA reductase and cytochrome c oxidase activities. The reductase present in microsomal preparations from the whole adrenal cortex has an apparent Km of 5.6 × 10−5 M for (R,S)-HMG-CoA. Reductase activities found in the microsomal fractions from the zona glomerulosa, the zona fasciculata, and the zona reticularis were 1.32, 7.37, and 9.74 nmol mevalonate formed per milligram protein in 30 min respectively.

scholarly journals Demonstration of poly-N-acetyl lactosamine residues in ameboid and ramified microglial cells in rat brain by tomato lectin binding.

1994 ◽  
Vol 42 (8) ◽  
pp. 1033-1041 ◽  
Author(s):  
L Acarin ◽  
J M Vela ◽  
B González ◽  
B Castellano
Keyword(s):  
Rat Brain ◽  
Glial Cells ◽  
Lectin Histochemistry ◽  
Adult Brain ◽  
Microglial Cells ◽  
Electron Microscopic Level ◽  
Sugar Residue ◽  
Adult Rat ◽  
Tomato Lectin ◽  
Adult Rat Brain

This study was designed to demonstrate the localization of poly-N-acetyl lactosamine residues in postnatal and adult rat brain, visualized by their specific binding to a lectin obtained from Lycopersicon esculentum (tomato). Lectin histochemistry was carried out on cryostat, paraffin, and vibratome sections and was examined by light microscopy. Selected vibratome sections were processed for electron microscopy. Our results showed that tomato lectin histochemistry was found in relation to blood vessels and glial cells in both postnatal and adult rat brain. Since tomato lectin-positive glial cells did not show GFAP immunoreactivity and displayed the same morphological features and overall distribution as nucleoside diphosphatase (NDPase)-positive cells, they were consequently identified as microglial cells. At the electron microscopic level, both ameboid and ramified microglial cells displayed intracytoplasmic and plasma membrane lectin reactivity. In postnatal brain, ameboid microglial cells always showed stronger binding of tomato lectin compared with ramified microglial cells in the adult brain. The putative significance of this decrease in poly-N-acetyl lactosamine from ameboid to ramified microglial cells and the possible role(s) of this sugar residue are discussed.

scholarly journals Nucleo-cytoplasmic relationships of high-molecular-weight ribonucleic acid, including polyadenylated species, in the developing rat brain

1976 ◽  
Vol 154 (2) ◽  
pp. 529-539 ◽  
Author(s):  
W Berthold ◽  
L Lim
Keyword(s):  
Molecular Weight ◽  
Rat Brain ◽  
High Molecular Weight ◽  
18S Rrna ◽  
Electrophoretic Analysis ◽  
Adult Brain ◽  
Considerable Proportion ◽  
Adult Rat ◽  
Polyadenylated Rna ◽  
Adult Rat Brain

The metabolism of high-molecular-weight RNA in the nuclear and cytoplasmic fractions of newborn and adult rat brain was investigated after the intracranial administration of [32P]Pi. In young brain, a considerable proportion of the newly synthesized radioactive RNA is transferred to the cytoplasm, in contrast with the adult brain, where there appears to be a high intranuclear turnover. Electrophoretic analysis of the newly synthesized RNA showed that processing of the rRNA precursor to yield the 28S and 18S rRNA may be more rapid in the adult than in the young, although most of the adult rRNA in the nucleus is not transferred to the cytoplasm. In young brain, processing is probably tightly coupled to transport of rRNA into the cytoplasm, so that 28S and 18S rRNA are not subjected to possible degradation within the nucleus. Polyadenylated RNA turns over in concert with high-molecular-weight RNA in the nuclei of the adult rat brain. In the cytoplasm the polyadenylated RNA has a higher turnover rate relative to rRNA. In the young brain the polyadenylated RNA is transferred to the cytoplasm along with rRNA, although polyadenylated RNA is transported into the cytoplasm at a faster rate. The nuclear and cytoplasmic polyadenylated RNA species of young brain are larger than their corresponding adult counterparts. These results suggest that there are considerable changes in the regulation of the nucleo-cytoplasmic relationship of rRNA and polyadenylated RNA during the transition of the brain from a developing replicative phase to an adult differentiated and non-dividing state.

scholarly journals Independent regulation of 3-hydroxy-3-methylglutaryl-coenzyme A reductase and chylomicron remnant receptor activities in rat liver

1984 ◽  
Vol 218 (1) ◽  
pp. 203-211 ◽  
Author(s):  
D P Wade ◽  
A K Soutar ◽  
G F Gibbons
Keyword(s):  
Coenzyme A ◽  
Binding Capacity ◽  
Reductase Activity ◽  
Intragastric Administration ◽  
Hmg Coa Reductase ◽  
Liver Membranes ◽  
Coa Reductase ◽  
Chylomicron Remnants ◽  
Coenzyme A Reductase

Treatment of rats with pharmacological doses of oestrogen resulted in a 3-fold decrease in the activity of hepatic 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMG-CoA reductase) and a 4-fold increase in saturable binding of 125I-labelled chylomicron remnants to liver membranes in vitro. Intragastric administration of mevalonolactone to rats did not affect the capacity of the liver membranes to bind to labelled chylomicron remnants even though there was a substantial decrease in the activity of HMG-CoA reductase. Similar results were obtained after cholesterol feeding. Simultaneous treatment of rats with cholestyramine and compactin increased hepatic HMG-CoA reductase activity 6-fold. However, liver membranes derived from these animals showed no change in their capacity to bind to labelled chylomicron remnants in vitro. Administration of mevalonolactone to the cholestyramine/compactin-treated animals also failed to produce a change in remnant-binding capacity. Although administration of mevalonolactone alone produced a significant 3-fold decrease in the activity of hepatic HMG-CoA reductase it was unable to suppress significantly the increase in enzyme activity caused by treatment with cholestyramine and compactin.

scholarly journals Acetoacetate metabolism in rat brain. Development of acetoacetyl-coenzyme A deacylase and 3-hydroxy-3-methylglutaryl-coenzyme A synthase

1978 ◽  
Vol 176 (3) ◽  
pp. 951-958 ◽  
Author(s):  
T B Patel ◽  
J B Clark
Keyword(s):  
Rat Brain ◽  
Coenzyme A ◽  
Substrate Inhibition ◽  
Kinetic Studies ◽  
Developmental Studies ◽  
Mitochondrial Preparation ◽  
Adult Rat ◽  
Total Brain ◽  
Adult Rat Brain

1. Data are provided that indicate that the rat brain acetoacetyl-CoA deacylase is almost exclusively mitochondrial. Developmental studies show that this enzyme more than doubles its activity during suckling (0–21 days) and then maintains this activity in adults (approx. 1.1 units/g wet wt.). 2. Kinetic studies (on the acetoacetyl-CoA deacylase) in a purified brain mitochondrial preparation give a Vmax. of 47 nmol/min per mg of protein, and a Km for acetoacetyl-CoA of 5.2 micron and are compatible with substrate inhibition by acetoacetyl-CoA above concentrations of 47 micron. 3. The total brain 3-hydroxy-3-methyl-glutaryl-CoA synthase remains constant in the developing and adult rat brain (approx. 1.2 units/g wet wt.). This enzyme is located in both the mitochondrial and cytosolic fractions. During suckling (0–21 days) the mitochondrial 3-hydroxy-3-methylglutaryl-CoA synthase represents approx. one-third of the total, but this increases markedly to about 60% of the total in the adult. The cytosolic enzyme correspondingly falls to approx. 40% of the total. 4. The role of the acetoacetyl-CoA deacylase in providing cytosolic acetoacetate for biosynthetic activities in the developing brain is discussed.

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