Alterations in glutamate dehydrogenase of the brain of rats of various ages

1970 ◽  
Vol 48 (2) ◽  
pp. 203-206 ◽  
Author(s):  
Gyan Kaur ◽  
M. S. Kanungo
Keyword(s):  
Protein Synthesis ◽  
Enzyme Activity ◽  
Glutamate Dehydrogenase ◽  
Nervous Tissue ◽  
Specific Activity ◽  
Old Rats ◽  
Total Dna ◽  
Regulatory Effects ◽  
The Brain ◽  
Inhibited Enzyme

The activity of glutamate dehydrogenase of the brain of 6-, 22-, 52-, and 96-week-old rats was determined. The specific activity, units per milligram DNA and units per organ, increased with growth and was highest at 22 weeks. This was probably due to a higher rate of protein synthesis during growth since the total DNA content did not change during this period. The activity declined in old age. Some biogenic amines, endogenous to nervous tissue and possibly having neurotransmitter functions, such as 5-hydroxy-tryptamine (5-HT), acetylcholine (ACh), and norepinephrine (NEp), inhibited enzyme activity; epinephrine (Ep) stimulated enzyme activity at all ages. Studies on the effects of various concentrations of the transmitters showed that the concentrations of 5-HT, ACh, NEp, and Ep producing significant regulatory effects on the enzyme may be 0.048, 0.18, 0.05, and 0.025 mg/ml, respectively.

scholarly journals The reaction of a histidine residue in glutamate dehydrogenase with diethyl pyrocarbonate

1973 ◽  
Vol 133 (1) ◽  
pp. 183-187 ◽  
Author(s):  
Robert B. Wallis ◽  
J. John Holbrook
Keyword(s):  
Molecular Weight ◽  
Enzyme Activity ◽  
Steady State ◽  
Glutamate Dehydrogenase ◽  
Specific Activity ◽  
Histidine Residue ◽  
Apparent Change ◽  
Diethyl Pyrocarbonate ◽  
Polypeptide Chains ◽  
Rate Limiting

1. One mol of diethyl pyrocarbonate will react with one mol of glutamate dehydrogenase polypeptide chains to form one mol of N1-carbethoxyhistidine. Reaction is prevented by NADH. 2. The 1:1 complex has an increased specific activity (1.4–2.0-fold). 3. The reason for the activation is discussed. The results are not consistent with NADH dissociation from the enzyme–glutamate–NADH complex being rate-limiting in the steady state measured. 4. The effects of modification on the properties of the enzyme were investigated. The effects of GTP and NAD+ on the enzyme activity are unaltered by activation. NADH binding is unaltered and there is no apparent change in the molecular weight. However, the activated enzyme can still be further activated by ADP. Ks for ADP is decreased fivefold.

scholarly journals Effects of glucose and insulin on the activation of lipoprotin lipase and on protein-synthesis in rat adipose tissue

1980 ◽  
Vol 188 (1) ◽  
pp. 193-199 ◽  
Author(s):  
S M Parkin ◽  
K Walker ◽  
P Ashby ◽  
D S Robinson
Keyword(s):  
Protein Synthesis ◽  
Enzyme Activity ◽  
Adipose Tissue ◽  
Lipoprotein Lipase ◽  
Specific Activity ◽  
The Other ◽  
Lipoprotein Lipase Activity ◽  
Fat Bodies ◽  
Rat Adipose Tissue ◽  
Adipose Tissue Lipoprotein Lipase

Glucose, and certain sugars that can readily be converted to glucose 6-phosphate, bring about an activation of adipose-tissue lipoprotein lipase when epididymal fat-bodies from starved rats are incubated in the presence of cycloheximide. Other substrates do not support the activation. If the tissue is preincubated in the presence of cycloheximide for longer than 2h, the ability of added glucose to activate the enzyme is lost. On the other hand, the addition of glucose still brings about an increase in lipoprotein lipase activity after preincubation in the absence of cycloheximide for as long as 4h. The magnitude of the increase in enzyme activity brought about by the addition of glucose is increased when protein synthesis is stimulated during the preincubation period by insulin. The results are interpreted in terms of the existence in adipose tissue of a proenzyme pool of lipoprotein lipase that is normally maintained by protein synthesis and that is converted to complete enzyme of higher specific activity by a process that specifically requires glucose.

scholarly journals The effect of elevated plasma phenylalanine levels on protein synthesis rates in adult rat brain

1994 ◽  
Vol 302 (2) ◽  
pp. 601-610 ◽  
Author(s):  
D S Dunlop ◽  
X R Yang ◽  
A Lajtha
Keyword(s):  
Protein Synthesis ◽  
Amino Acid ◽  
Free Amino ◽  
Specific Activity ◽  
Brain Protein ◽  
Free Amino Acid Pool ◽  
Plasma Phenylalanine ◽  
Specific Activities ◽  
Brain Protein Synthesis ◽  
The Brain

Increasing the plasma phenylalanine concentration to levels as high as 0.560-0.870 mM (over ten times normal levels) had no detectable effect on the rate of brain protein synthesis in adult rats. The average rates for 7-week-old rats were: valine, 0.58 +/- 0.05%/h, phenylalanine, 0.59 +/- 0.06%/h, and tyrosine, 0.60 +/- 0.09%/h, or 0.59 +/- 0.06%/h overall. Synthesis rates calculated on the basis of the specific activity of the tRNA-bound amino acid were slightly lower (4% lower for phenylalanine) than those based on the brain free amino acid pool. Similarly, the specific activities of valine and phenylalanine in microdialysis fluid from striatum were practically the same as those in the brain free amino acid pool. Thus the specific activities of the valine and phenylalanine brain free pools are good measures of the precursor specific activity for protein synthesis. In any event, synthesis rates, whether based on the specific activities of the amino acids in the brain free pool or those bound to tRNA, were unaffected by elevated levels of plasma phenylalanine. Brain protein synthesis rates measured after the administration of quite large doses of phenylalanine (> 1.5 mumol/g) or valine (15 mumol/g) were in agreement (0.62 +/- 0.01 and 0.65 +/- 0.01%/h respectively) with the rates determined with infusions of trace amounts of amino acids. Thus the technique of stabilizing precursor-specific activity, and pushing values in the brain close to those of the plasma, by the administration of large quantities of precursor, appears to be valid.

Changes in regional protein synthesis in rat brain and pituitary after systemic interleukin-1 beta administration

1994 ◽  
Vol 267 (6) ◽  
pp. E915-E920
Author(s):  
L. M. Williams ◽  
P. E. Ballmer ◽  
L. T. Hannah ◽  
I. Grant ◽  
P. J. Garlick
Keyword(s):  
Protein Synthesis ◽  
Specific Activity ◽  
Interleukin 1 ◽  
Interleukin 1 Beta ◽  
High Concentration ◽  
Mediated Effects ◽  
Amino Acid Precursor ◽  
Cryostat Sections ◽  
The Brain ◽  
Acid Precursor

A convenient and sensitive method has been developed for measuring changes in protein synthesis in discrete areas of the brain and pituitary of conscious freely moving rats. A single injection of high-concentration low-specific activity L-[35S]methionine is given to flood amino acid precursor pools, thereby equalizing the specific activity of the L-[35S]methionine throughout the tissue. Unincorporated L-[35S]methionine is removed from cryostat sections by treatment with perchloric acid (2%) before quantitative autoradiography. The sensitivity of this technique is demonstrated by the detection of changes in protein synthesis in regions of the brain and pituitary after systemic administration of interleukin-1 beta, a cytokine that has centrally mediated effects but which is not thought to cross the blood-brain barrier. Areas of the brain found to exhibit significant increases in protein synthesis were the subfornical organ, the choroid plexus, the medial habenular, the dentate gyrus, and the anterior and posterior lobes of the pituitary. In the brain, the cingulate cortex and the pineal gland showed significant decreases in the rate of protein synthesis.

scholarly journals The effect of hyperphenylalaninaemia on glycine metabolism in developing rat brain

1980 ◽  
Vol 192 (2) ◽  
pp. 441-448 ◽  
Author(s):  
C E Isaacs ◽  
O Greengard
Keyword(s):  
Specific Activity ◽  
Later Life ◽  
Early Postnatal Development ◽  
Plasma Phenylalanine ◽  
Glycine Metabolism ◽  
Old Rats ◽  
Branched Chain ◽  
Developing Rat ◽  
The Brain ◽  
Glycine Content

The brains of 3–16-day-old rats that were rendered hyperphenylalaninaemic by daily injections of alpha-methylphenylalanine plus phenylalanine were subjected to biochemical analysis. Fluctuations throughout the treatment period in the concentrations of branched-chain amino acids, methionine and serotonin were in agreement with the known interference of excess plasma phenylalanine with transport. The glycine content, however, became abnormal only by day 5, remained so through the treatment, and the elevation was equally apparent at 4, 8 or 24 h after the last daily injections. On the last day of treatment there were small increases in the taurine, glutamate, aspartate and 4-aminobutyrate concentrations, attributable mainly to the diencephalon or brain stem. After day 3 of treatment there were persistent elevations in the specific activity of phosphoserine phosphatase and glycine synthase (but not serine hydroxymethyltransferase) of the brain in each of the regions analysed. The observations indicate that chronic hyperphenylalaninaemia interferes with the normal regulation of intracerebral glycine metabolism during a critical period of early postnatal development, and suggest that the resulting excess in this amino acid (particularly marked in the cortex) contributes to the behavioural abnormalities that these animals exhibit in later life.

Endotoxin Alteration of the Mucopolysaccharide Blood Vessel Coating in Rats

1974 ◽  
Vol 32 ◽  
pp. 148-149
Author(s):  
D. E. Philpott ◽  
A. Takahashi
Keyword(s):  
Skeletal Muscle ◽  
Endothelial Cells ◽  
Salivary Gland ◽  
Carotid Artery ◽  
Basement Membrane ◽  
Coronary Vessels ◽  
Ruthenium Red ◽  
E Coli ◽  
Old Rats ◽  
The Brain

Two month, eight month and two year old rats were treated with 10 or 20 mg/kg of E. Coli endotoxin I. P. The eight month old rats proved most resistant to the endotoxin. During fixation the aorta, carotid artery, basil arartery of the brain, coronary vessels of the heart, inner surfaces of the heart chambers, heart and skeletal muscle, lung, liver, kidney, spleen, brain, retina, trachae, intestine, salivary gland, adrenal gland and gingiva were treated with ruthenium red or alcian blue to preserve the mucopolysaccharide (MPS) coating. Five, 8 and 24 hrs of endotoxin treatment produced increasingly marked capillary damage, disappearance of the MPS coating, edema, destruction of endothelial cells and damage to the basement membrane in the liver, kidney and lung.

scholarly journals A novel PET tracer 18F-deoxy-thiamine: synthesis, metabolic kinetics, and evaluation on cerebral thiamine metabolism status

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Changpeng Wang ◽  
Siwei Zhang ◽  
Yuefei Zou ◽  
Hongzhao Ma ◽  
Donglang Jiang ◽  
...  
Keyword(s):  
High Performance ◽  
Specific Activity ◽  
High Accumulation ◽  
Metabolic Kinetics ◽  
Thiamine Metabolism ◽  
Pet Tracer ◽  
The Status ◽  
The Brain

Abstract Background Some neuropsychological diseases are associated with abnormal thiamine metabolism, including Korsakoff–Wernicke syndrome and Alzheimer’s disease. However, in vivo detection of the status of brain thiamine metabolism is still unavailable and needs to be developed. Methods A novel PET tracer of 18F-deoxy-thiamine was synthesized using an automated module via a two-step route. The main quality control parameters, such as specific activity and radiochemical purity, were evaluated by high-performance liquid chromatography (HPLC). Radiochemical concentration was determined by radioactivity calibrator. Metabolic kinetics and the level of 18F-deoxy-thiamine in brains of mice and marmosets were studied by micro-positron emission tomography/computed tomography (PET/CT). In vivo stability, renal excretion rate, and biodistribution of 18F-deoxy-thiamine in the mice were assayed using HPLC and γ-counter, respectively. Also, the correlation between the retention of cerebral 18F-deoxy-thiamine in 60 min after injection as represented by the area under the curve (AUC) and blood thiamine levels was investigated. Results The 18F-deoxy-thiamine was stable both in vitro and in vivo. The uptake and clearance of 18F-deoxy-thiamine were quick in the mice. It reached the max standard uptake value (SUVmax) of 4.61 ± 0.53 in the liver within 1 min, 18.67 ± 7.04 in the kidney within half a minute. The SUV dropped to 0.72 ± 0.05 and 0.77 ± 0.35 after 60 min of injection in the liver and kidney, respectively. After injection, kidney, liver, and pancreas exhibited high accumulation level of 18F-deoxy-thiamine, while brain, muscle, fat, and gonad showed low accumulation concentration, consistent with previous reports on thiamine distribution in mice. Within 90 min after injection, the level of 18F-deoxy-thiamine in the brain of C57BL/6 mice with thiamine deficiency (TD) was 1.9 times higher than that in control mice, and was 3.1 times higher in ICR mice with TD than that in control mice. The AUC of the tracer in the brain of marmosets within 60 min was 29.33 ± 5.15 and negatively correlated with blood thiamine diphosphate levels (r = − 0.985, p = 0.015). Conclusion The 18F-deoxy-thiamine meets the requirements for ideal PET tracer for in vivo detecting the status of cerebral thiamine metabolism.

scholarly journals LSD1 enzyme inhibitor TAK-418 unlocks aberrant epigenetic machinery and improves autism symptoms in neurodevelopmental disorder models

2021 ◽  
Vol 7 (11) ◽  
pp. eaba1187
Author(s):  
Rina Baba ◽  
Satoru Matsuda ◽  
Yuuichi Arakawa ◽  
Ryuji Yamada ◽  
Noriko Suzuki ◽  
...  
Keyword(s):  
Gene Expression ◽  
Enzyme Activity ◽  
Neurodevelopmental Disorders ◽  
Neurodevelopmental Disorder ◽  
Specific Inhibitor ◽  
Autism Spectrum ◽  
Poly I:C ◽  
Control Of Gene Expression ◽  
Epigenetic Machinery ◽  
The Brain

Persistent epigenetic dysregulation may underlie the pathophysiology of neurodevelopmental disorders, such as autism spectrum disorder (ASD). Here, we show that the inhibition of lysine-specific demethylase 1 (LSD1) enzyme activity normalizes aberrant epigenetic control of gene expression in neurodevelopmental disorders. Maternal exposure to valproate or poly I:C caused sustained dysregulation of gene expression in the brain and ASD-like social and cognitive deficits after birth in rodents. Unexpectedly, a specific inhibitor of LSD1 enzyme activity, 5-((1R,2R)-2-((cyclopropylmethyl)amino)cyclopropyl)-N-(tetrahydro-2H-pyran-4-yl)thiophene-3-carboxamide hydrochloride (TAK-418), almost completely normalized the dysregulated gene expression in the brain and ameliorated some ASD-like behaviors in these models. The genes modulated by TAK-418 were almost completely different across the models and their ages. These results suggest that LSD1 enzyme activity may stabilize the aberrant epigenetic machinery in neurodevelopmental disorders, and the inhibition of LSD1 enzyme activity may be the master key to recover gene expression homeostasis. TAK-418 may benefit patients with neurodevelopmental disorders.

scholarly journals Muscle and Liver Protein Synthesis Adapt Efficiently to Food Deprivation and Refeeding in 12-Month-Old Rats

1996 ◽  
Vol 126 (2) ◽  
pp. 516-522 ◽  
Author(s):  
Laurent Mosoni ◽  
Thierry Malmezat ◽  
Marie-Claude Valluy ◽  
Marie-Louise Houlier ◽  
Philippe Patureau Mirand
Keyword(s):  
Protein Synthesis ◽  
Food Deprivation ◽  
Liver Protein ◽  
Old Rats
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