scholarly journals Enzymes involved in adenosine metabolism in rat white and brown adipocytes. Effects of streptozotocin-diabetes, hypothyroidism, age and sex differences

1987 ◽  
Vol 245 (3) ◽  
pp. 881-886 ◽  
Author(s):  
Z Jamal ◽  
E D Saggerson
Keyword(s):  
Adenosine Deaminase ◽  
Streptozotocin Diabetes ◽  
Adenosine Kinase ◽  
Female Rats ◽  
Male Rats ◽  
Nucleotidase Activity ◽  
Brown Adipocytes ◽  
Cell Extracts ◽  
White Adipocytes ◽  
Adenosine Deaminase Activity

1. Adipocytes were isolated from epididymal white fat and interscapular brown fat of male rats, and activities of 5′-nucleotidase, adenosine deaminase and adenosine kinase were measured in cell extracts. 2. 5′-Nucleotidase activity in white adipocytes was increased in streptozotocin-diabetes, decreased in hypothyroidism and increased with age. That activity in brown adipocytes was unchanged in diabetes, decreased in hypothyroidism and increased with age. 5′-Nucleotidase activity was higher in white adipocytes from female rats. 3. Adenosine deaminase activity in white adipocytes was increased in diabetes, decreased in hypothyroidism and increased with age. That activity in brown adipocytes was decreased in diabetes and hypothyroidism. 4. Adenosine kinase activity in both cell types was unchanged in diabetes or hypothyroidism, but increased with age.

scholarly journals Comparison of triacylglycerol synthesis in rat brown and white adipocytes. Effects of hypothyroidism and streptozotocin-diabetes on enzyme activities and metabolic fluxes

1988 ◽  
Vol 250 (2) ◽  
pp. 325-333 ◽  
Author(s):  
H S Baht ◽  
E D Saggerson
Keyword(s):  
Fatty Acid ◽  
Enzyme Activities ◽  
Metabolic Flux ◽  
Streptozotocin Diabetes ◽  
Fatty Acyl ◽  
Brown Adipocyte ◽  
Acid Oxidation ◽  
Brown Adipocytes ◽  
Triacylglycerol Synthesis ◽  
White Adipocytes

1. Adipocytes were isolated from the interscapular brown fat and the epididymal white fat of normal, streptozotocin-diabetic and hypothyroid rats. 2. Measurements were made of the maximum rate of triacylglycerol synthesis by monitoring the incorporation of [U-14C]glucose into acylglycerol glycerol in the presence of palmitate (1 mM) and insulin (4 nM) and of the activities of the following triacylglycerol-synthesizing enzymes: fatty acyl-CoA synthetase (FAS), mitochondrial and microsomal forms of glycerolphosphate acyltransferase (GPAT), dihydroxyacetonephosphate acyltransferase (DHAPAT), monoacylglycerol phosphate acyltransferase (MGPAT), Mg2+-dependent phosphatidate phosphohydrolase (PPH) and diacylglycerol acyltransferase (DGAT). 3. FAS activity in brown adipocytes was predominantly localized in the mitochondrial fraction, whereas a microsomal localization of this enzyme predominated in white adipocytes. Subcellular distributions of the other enzyme activities in brown adipocytes were similar to those shown previously with white adipocytes [Saggerson, Carpenter, Cheng & Sooranna (1980) Biochem. J. 190, 183-189]. 4. Relative to cell DNA, brown adipocytes had lower activities of triacylglycerol-synthesizing enzymes and showed lower rates of metabolic flux into acylglycerols than did white adipocytes isolated from the same animals. 5. Diabetes decreased both metabolic flux into acylglycerols and the activities of triacylglycerol-synthesizing enzymes in white adipocytes. By contrast, although diabetes decreased metabolic flux into brown-adipocyte acylglycerols by 80%, there were no decreases in the activities of triacylglycerol-synthesizing enzymes, and the activity of PPH was significantly increased. 6. Hypothyroidism increased metabolic flux into acylglycerols in both cell types, and increased activities of all triacylglycerol-synthesizing enzymes in brown adipocytes. By contrast, in white adipocytes, although hypothyroidism increased the activities of FAS, microsomal GPAT and DGAT, this condition decreased the activities of mitochondrial GPAT and PPH. 7. It was calculated that the maximum capabilities for fatty acid oxidation and esterification are approximately equal in brown adipocytes. In white adipocytes esterification is predominant by approx. 100-fold. 8. Diabetes almost abolished incorporation of [U-14C]glucose into fatty acids in both adipocyte types. Hypothyroidism increased fatty acid synthesis in white and brown adipocytes by 50% and 1000% respectively.

scholarly journals STUDY THE EFFECT OF ADENOSINE DEAMINASE ENZYME IN INDUCES CYTOGENETIC AND HISTOPATHOLOGICAL CHANGES IN RATS SKIN AND EYES TREATED WITH SUMICIDIN

2000 ◽  
Vol 24 (2) ◽  
pp. 88-111
Author(s):  
Bushra Ibrahim Al-Qaisi
Keyword(s):  
Adenosine Deaminase ◽  
Serum Protein ◽  
White Male ◽  
Normal Diet ◽  
Male Rats ◽  
Total Serum Protein ◽  
Total Serum ◽  
Histopathological Changes ◽  
Adenosine Deaminase Activity ◽  
Group 1

The present investigation aimed to study the Adenosine Deaminase activity in induction Cytogentic and histopathological change in skin and eyes of sumicidine treated rats. The study Included. 1-Adenosine deaminase activity . 2-Total serum protein. 3-Micronuclei in binucleated cell. 4-Histopathological changes in skin and eyes.  19 white male rats were used . They are randomly allocated into 3 groups : 1st group was fed 2% sumicidine for 15 days. 2nd group was fed 2% heating sumicidine for 15 days . 3rd group was kept on normal diet. Blood Adenosine Deaminase activity and Total serum protein in 1 and 2 group significantly decreased at 15 and 30 days of treated. The results  indicated that sumicidine increased significantly micronucleus in group 1 and 2. Multifocal granulomatous lesions in skin & eyes of group 1 and 2 were found characterized by highly aggregation of cells (Lymphocytes, Macrophages, Foreign body giant cells and fibroblasts).  In conclusion , Sumicidine even heated accompaying in decreased in decreased Adenosine Deaminase activity and total serum protein , in part a possible factor in the cytogenetic effect and accompanying granuloma formation in skin and eye . 

The catalytic activity of adenosine monophosphate deaminase in murine duodenum as revealed by transmission electron microscopy

1993 ◽  
Vol 51 ◽  
pp. 302-303
Author(s):  
K. Bielat ◽  
G. Tritsch
Keyword(s):  
Adenosine Deaminase ◽  
Adenosine Monophosphate ◽  
Rabbit Muscle ◽  
Amp Deaminase ◽  
Nucleotidase Activity ◽  
Previous Approach ◽  
Muscle Enzyme ◽  
Transmission Electron ◽  
Adenosine Deaminase Activity ◽  
Excised Tissue

AMP deaminase was visualized in a manner analogous to our previous approach with adenosine deaminase. The chloro-analog of AMP, i.e., 6 Chloropurine riboside 5' monophosphate (CPRMP) (from Sigma) was shown to be a substrate of this enzyme which liberates Cl- which is precipitated with added Ag+, and, after exposure to light electron dense Ag° grains are deposited at loci of enzyme activity. The substrate at a concentration of 1.1 mM in 50 mM HEPES buffer, pH 7.2, in the presence of 150 mM K+ (as the acetate), 3mM ATP and 10¼M pentostathi (deoxycoformycin) was incubated with freshly excised tissue from a female C-57 BL/6 mouse. The substrate concentration is 1.4 times Km for rabbit muscle enzyme (Sigma), and K+ and ATP are allosteric activators of this enzyme. Because many cells have ecto 5'-nucleotidase activity, pentostathi was added to prevent manifestation of adenosine deaminase activity of dechlorination of any nucleoside that might be formed.

scholarly journals Demonstration of adenosine deaminase activity in human fibroblast lysosomes

1993 ◽  
Vol 290 (2) ◽  
pp. 457-462 ◽  
Author(s):  
E R Lindley ◽  
R L Pisoni
Keyword(s):  
Adenosine Deaminase ◽  
Human Fibroblast ◽  
Human Fibroblasts ◽  
Maximal Activity ◽  
Adenosine Kinase ◽  
Cellular Energy ◽  
Nutritional Deprivation ◽  
Heat Stable ◽  
Bivalent Cations ◽  
Adenosine Deaminase Activity

Human fibroblast lysosomes, purified on Percoll density gradients, contain an adenosine deaminase (ADA) activity that accounts for approximately 10% of the total ADA activity in GM0010A human fibroblasts. In assays of lysosomal ADA, the conversion of [3H]adenosine into [3H]inosine was proportional to incubation time and the amount of lysosomal material added to reaction mixtures. Maximal activity was observed between pH 7 and 8, and lysosomal ADA displayed a Km of 37 microM for adenosine at 25 degrees C and pH 5.5. Lysosomal ADA was completely inhibited by 2.5 mM Cu2+ or Hg2+ salts, but not by other bivalent cations (Ba2+, Cd2+, Ca2+, Fe2+, Mg2+, Mn2+ and Zn2+). Coformycin (2.5 mM), deoxycoformycin (0.02 mM), 2′-deoxyadenosine (2.5 mM), 6-methylaminopurine riboside (2.5 mM), 2′-3′-isopropylidene-adenosine (2.5 mM) and erythro-9-(2-hydroxy-3-nonyl)adenine (0.2 mM) inhibited lysosomal ADA by > 97%. In contrast, 2.5 mM S-adenosyl-L-homocysteine and cytosine were poor inhibitors. Nearly all lysosomal ADA activity is eluted as a high-molecular-mass protein (> 200 kDa) just after the void volume on a Sephacryl S-200 column, and is very heat-stable, retaining 70% of its activity after incubation at 65 degrees C for 80 min. We speculate that compartmentalization of ADA within lysosomes would allow deamination of adenosine to occur without competition by adenosine kinase, which could assist in maintaining cellular energy requirements under conditions of nutritional deprivation.

scholarly journals Changes in the activities of adenosine-metabolizing enzymes in six regions of the rat brain on chemical induction of hypothyroidism

1989 ◽  
Vol 261 (2) ◽  
pp. 667-672 ◽  
Author(s):  
D Mazurkiewicz ◽  
D Saggerson
Keyword(s):  
Neurotransmitter Release ◽  
Kinase Activity ◽  
Adenosine Kinase ◽  
Nucleotidase Activity ◽  
Chemical Induction ◽  
Metabolizing Enzymes ◽  
Adenosine Deaminase Activity ◽  
Membrane Bound ◽  
The Brain ◽  
Soluble Fractions

1. Rats (4 weeks old) were made hypothyroid by treatment with propylthiouracil and a low-iodine diet for a further period of 4 weeks. Synaptosomal membranes, myelin and 105,000 g soluble fractions were obtained from six regions of the brain. 2. Hypothyroidism resulted in 2-5-fold increases in membrane-bound 5′-nucleotidase activity in synaptosomal fractions obtained from cerebellum, cortex, striatum and hippocampus. By contrast, myelin 5′-nucleotidase activity was slightly increased only in the medulla oblongata. 3. Hypothyroidism did not change adenosine deaminase activity, but decreased adenosine kinase activity by approx. 40% in soluble fractions obtained from cerebellum, hippocampus, striatum and hypothalamus. 4. It is suggested that these changes in hypothyroidism, in particular the increases in 5′-nucleotidase activity, could enhance the neuromodulatory effect of adenosine to decrease neurotransmitter release.

TEM of the catalytic activity of adenosine monophosphate deaminase in murine lung

1992 ◽  
Vol 50 (1) ◽  
pp. 794-795
Author(s):  
K. Bielat ◽  
G. Tritsch
Keyword(s):  
Adenosine Deaminase ◽  
Adenosine Monophosphate ◽  
Rabbit Muscle ◽  
Amp Deaminase ◽  
Nucleotidase Activity ◽  
Previous Approach ◽  
Muscle Enzyme ◽  
Murine Lung ◽  
Adenosine Deaminase Activity ◽  
Excised Tissue

AMP deaminase was visualized in a manner analogous to our previous approach with adenosine deaminase. The chloro-analog of AMP, i.e., 6 Chloropurine riboside 5’ monophosphate (CPRMP) (from Sigma) was shown to be a substrate of this enzyme which 1iberates Cl− which is precipitated with added Ag+, and, after exposure to light electron dense Ag° grains are deposited at loci of enzyme activity. The substrate at a concentration of 1.1 mM in 50 mM HEPES buffer, pH 7.2, in the presence of 150 mM K+ (as the acetate), 3mM ATP and 10μM pentostatin (deoxycoformycin) was incubated with freshly excised tissue from a female C-57 BL/6 mouse. The substrate concentration is 1.4 times Km for rabbit muscle enzyme (Sigma), and K+ and ATP are allosteric activators of this enzyme. Because many cells have ecto 5’-nucleotidase activity, pentostatin was added to prevent manifestation of adenosine deaminase activity of dechlorination of any nucleoside that might be formed.

scholarly journals Lipogenesis in rat brown adipocytes. Effects of insulin and noradrenaline, contributions from glucose and lactate as precursors and comparisons with white adipocytes

1988 ◽  
Vol 251 (3) ◽  
pp. 701-709 ◽  
Author(s):  
E D Saggerson ◽  
T W J McAllister ◽  
H S Baht
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Fatty Acid Synthesis ◽  
Acid Synthesis ◽  
Male Rats ◽  
Brown Adipocytes ◽  
Exogenous Fatty Acid ◽  
Fat Depots ◽  
White Adipocytes ◽  
Brown Adipose

1. Brown adipocytes were isolated from the interscapular depot of male rats maintained at approx. 21 degrees C. In some experiments parallel studies were made with white adipocytes from the epididymal depot. 2. Insulin increased and noradrenaline decreased [U-14C]glucose incorporation into fatty acids by brown adipocytes. Brown adipocytes differed from white adipocytes in that exogenous fatty acid (palmitate) substantially decreased fatty acid synthesis from glucose. Both noradrenaline and insulin increased lactate + pyruvate formation by brown adipocytes. Brown adipocytes converted a greater proportion of metabolized glucose into lactate + pyruvate and a smaller proportion into fatty acids than did white adipocytes. 3. In brown adipocytes, when fatty acid synthesis from [U-14C]glucose was decreased by noradrenaline or palmitate, incorporation of 3H2O into fatty acids was also decreased to an extent which would not support proposals for extensive recycling into fatty acid synthesis of acetyl-CoA derived from fatty acid oxidation. 4. In the absence of glucose, [U-14C]lactate was a poor substrate for lipogenesis in brown adipocytes, but its use was facilitated by glucose. When brown adipocytes were incubated with 1 mM-lactate + 5 mM-glucose, lactate-derived carbon generally provided at least 50% of the precursor for fatty acid synthesis. 5. Both insulin and noradrenaline increased [U-14C]glucose conversion into CO2 by brown adipocytes (incubated in the presence of lactate) and, in combination, stimulation of glucose oxidation by these two agents showed synergism. Rates of 14CO2 formation from glucose by brown adipocytes were relatively small compared with maximum rates of oxygen consumption by these cells, suggesting that glucose is unlikely to be a major substrate for thermogenesis. 6. Brown adipocytes from 6-week-old rats had considerably lower maximum rates of fatty acid synthesis, relative to cell DNA content, than white adipocytes. By contrast, rates of fatty acid synthesis from 3H2O in vivo were similar in the interscapular and epididymal fat depots. Expressed relative to activities of fatty acid synthase or ATP citrate lyase, however, brown adipocytes synthesized fatty acids as effectively as did white adipocytes. It is suggested that the cells most active in fatty acid synthesis in the brown adipose tissue are not recovered fully in the adipocyte fraction during cell isolation. Differences in rates of fatty acid synthesis between brown and white adipocytes were less apparent at 10 weeks of age.

scholarly journals Adenosine turnover in GtoPdb v.2021.3

2021 ◽  
Vol 2021 (3) ◽  
Author(s):  
Detlev Boison
Keyword(s):  
Cell Surface ◽  
Adenosine Deaminase ◽  
Inorganic Phosphate ◽  
G Protein Coupled Receptors ◽  
Adenosine Kinase ◽  
Nucleoside Transporters ◽  
Nucleotidase Activity ◽  
Extracellular Adenosine ◽  
Adenosylhomocysteine Hydrolase ◽  
G Protein Coupled

A multifunctional, ubiquitous molecule, adenosine acts at cell-surface G protein-coupled receptors, as well as numerous enzymes, including protein kinases and adenylyl cyclase. Extracellular adenosine is thought to be produced either by export or by metabolism, predominantly through ecto-5’-nucleotidase activity (also producing inorganic phosphate). It is inactivated either by extracellular metabolism via adenosine deaminase (also producing ammonia) or, following uptake by nucleoside transporters, via adenosine deaminase or adenosine kinase (requiring ATP as co-substrate). Intracellular adenosine may be produced by cytosolic 5’-nucleotidases or through S-adenosylhomocysteine hydrolase (also producing L-homocysteine).

scholarly journals Adenosine turnover (version 2019.4) in the IUPHAR/BPS Guide to Pharmacology Database

2019 ◽  
Vol 2019 (4) ◽  
Author(s):  
Detlev Boison
Keyword(s):  
Cell Surface ◽  
Adenosine Deaminase ◽  
Inorganic Phosphate ◽  
G Protein Coupled Receptors ◽  
Adenosine Kinase ◽  
Nucleoside Transporters ◽  
Nucleotidase Activity ◽  
Extracellular Adenosine ◽  
Adenosylhomocysteine Hydrolase ◽  
G Protein Coupled

A multifunctional, ubiquitous molecule, adenosine acts at cell-surface G protein-coupled receptors, as well as numerous enzymes, including protein kinases and adenylyl cyclase. Extracellular adenosine is thought to be produced either by export or by metabolism, predominantly through ecto-5’-nucleotidase activity (also producing inorganic phosphate). It is inactivated either by extracellular metabolism via adenosine deaminase (also producing ammonia) or, following uptake by nucleoside transporters, via adenosine deaminase or adenosine kinase (requiring ATP as co-substrate). Intracellular adenosine may be produced by cytosolic 5’-nucleotidases or through S-adenosylhomocysteine hydrolase (also producing L-homocysteine).

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