METHYLATION OF THE 3-OH POSITION OF CATECHOL ACIDS BY RAT LIVER AND KIDNEY PREPARATIONS

1958 ◽  
Vol 36 (5) ◽  
pp. 491-497 ◽  
Author(s):  
J. Pellerin ◽  
A. D'Iorio
Keyword(s):  
Enzymatic Activity ◽  
Rat Liver ◽  
Paper Chromatography ◽  
Reduced Glutathione ◽  
Liver Homogenate ◽  
Supernatant Fraction ◽  
Hydroxybenzoic Acid ◽  
Dihydroxybenzoic Acid ◽  
Kidney Homogenate ◽  
Liver And Kidney

3,4-Dihydroxybenzoic acid, 3,4-dihydroxyphenylacetic acid, 3,4-dihydroxymandelic acid, and 3,4-dihydroxycinnamic acid were separately incubated with L-methionine-methyl-C14 in the presence of rat liver or kidney homogenate. In each case, the radioactive metabolite separated by paper chromatography was found to have migrating properties similar to those of the 3-methoxy-4-hydroxyphenolic acid. This reaction was enhanced by the addition of ATP, Mg++, and reduced glutathione. When 3-hydroxybenzoic acid was incubated in this medium no methylated derivative was obtained. Preliminary experiments indicated that the enzymatic activity was contained mostly in the supernatant fraction. It was also noted that liver homogenate was much more active than kidney homogenate in methylating catechol acids.

METHYLATION OF THE 3-OH POSITION OF CATECHOL ACIDS BY RAT LIVER AND KIDNEY PREPARATIONS

1958 ◽  
Vol 36 (1) ◽  
pp. 491-497 ◽  
Author(s):  
J. Pellerin ◽  
A. D'Iorio
Keyword(s):  
Enzymatic Activity ◽  
Rat Liver ◽  
Paper Chromatography ◽  
Reduced Glutathione ◽  
Liver Homogenate ◽  
Supernatant Fraction ◽  
Hydroxybenzoic Acid ◽  
Dihydroxybenzoic Acid ◽  
Kidney Homogenate ◽  
Liver And Kidney

3,4-Dihydroxybenzoic acid, 3,4-dihydroxyphenylacetic acid, 3,4-dihydroxymandelic acid, and 3,4-dihydroxycinnamic acid were separately incubated with L-methionine-methyl-C14 in the presence of rat liver or kidney homogenate. In each case, the radioactive metabolite separated by paper chromatography was found to have migrating properties similar to those of the 3-methoxy-4-hydroxyphenolic acid. This reaction was enhanced by the addition of ATP, Mg++, and reduced glutathione. When 3-hydroxybenzoic acid was incubated in this medium no methylated derivative was obtained. Preliminary experiments indicated that the enzymatic activity was contained mostly in the supernatant fraction. It was also noted that liver homogenate was much more active than kidney homogenate in methylating catechol acids.

Biosynthesis of 1,2-3H and 4-14C steroid sulfates of high specific activity

1970 ◽  
Vol 48 (1) ◽  
pp. 148-150 ◽  
Author(s):  
J. Torday ◽  
G. Hall ◽  
M. Schweitzer ◽  
C. J. P. Giroud
Keyword(s):  
Rat Liver ◽  
Specific Activity ◽  
Liver Homogenate ◽  
High Specific Activity ◽  
Supernatant Fraction ◽  
Metabolic Studies

A supernatant fraction of rat liver homogenate enriched with ATP was used for the biosynthesis of the ester sulfates of several 3H and 14C steroids of the pregn-4-ene series. The method provides a simple means to prepare steroid sulfates of high specific activity for use in either metabolic studies or as reference compounds in the quantification of such conjugates by isotope assays.

scholarly journals The function of subcellular fractions in the oxidation of glutathione in rat liver homogenate

1970 ◽  
Vol 117 (5) ◽  
pp. 951-956 ◽  
Author(s):  
P. C. Jocelyn
Keyword(s):  
Uric Acid ◽  
Xanthine Oxidase ◽  
Rat Liver ◽  
Liver Homogenate ◽  
No Oxidation ◽  
Urate Oxidase ◽  
Supernatant Fraction ◽  
Endogenous Substrate ◽  
Additional Protein ◽  
Microsome Fraction

1. The aerobic loss of GSH added to the supernatant fraction from rat liver is much increased by including the microsome fraction, which both inhibits the concurrent reduction of the GSSG formed and also augments the net oxidation rate. 2. Oxidation occurs with a mixture of dialysed supernatant and a protein-free filtrate; the latter is replaceable by hypoxanthine and the former by xanthine oxidase, whereas fractions lacking this enzyme give no oxidation. 3. In all these instances augmentation occurs with microsomes, with fractions having urate oxidase activity and with the purified enzyme; uric acid and microsomes alone also support the oxidation. 4. Evidence implicating additional protein factors is discussed. 5. It is suggested that GSH oxidation by homogenate is linked through glutathione peroxidase to the reaction of endogenous substrate with supernatant xanthine oxidase and of the uric acid formed with peroxisomal urate oxidase.

scholarly journals Two forms of aspartate aminotransferase in rat liver and kidney mitochondria

1968 ◽  
Vol 108 (4) ◽  
pp. 619-624 ◽  
Author(s):  
M. M. Bhargava ◽  
A. Sreenivasan
Keyword(s):  
Rat Liver ◽  
Aspartate Aminotransferase ◽  
High Speed ◽  
Rat Kidney ◽  
Liver Mitochondria ◽  
Supernatant Fraction ◽  
Rat Liver Mitochondria ◽  
Aminotransferase Activity ◽  
Kidney Mitochondria ◽  
Liver And Kidney

1. Butan-1-ol solubilizes that portion of rat liver mitochondrial aspartate aminotransferase (EC 2.6.1.1) that cannot be solubilized by ultrasonics and other treatments. 2. A difference in electrophoretic mobilities, chromatographic behaviour and solubility characteristics between the enzymes solubilized by ultrasonic treatment and by butan-1-ol was observed, suggesting the occurrence of two forms of this enzyme in rat liver mitochondria. 3. Half the aspartate aminotransferase activity of rat kidney homogenate was present in a high-speed supernatant fraction, the remainder being in the mitochondria. 4. A considerable increase in aspartate aminotransferase activity was observed when kidney mitochondrial suspensions were treated with ultrasonics or detergents. 5. All the activity after maximum activation was recoverable in the supernatant after centrifugation at 105000g for 1hr. 6. The electrophoretic mobility of the kidney mitochondrial enzyme was cathodic and that of the supernatant enzyme anodic. 7. Cortisone administration increased the activities of both mitochondrial and supernatant aspartate aminotransferases of liver, but only that of the supernatant enzyme of kidney.

PARTIAL SEPARATION OF A 3α-KETOSTEROID OXIDOREDUCTASE AND AN ANDROGEN BINDING SUBSTANCE PRESENT IN RAT VENTRAL PROSTATE CYTOPLASM

1970 ◽  
Vol 65 (3) ◽  
pp. 525-532 ◽  
Author(s):  
Olav Unhjem
Keyword(s):  
Enzymatic Activity ◽  
Reduced Glutathione ◽  
Enzymatic Reaction ◽  
Gel Filtration ◽  
Ventral Prostate ◽  
Supernatant Fraction ◽  
Rat Ventral Prostate ◽  
Molecular Sizes ◽  
Androgen Binding ◽  
Fraction Addition

ABSTRACT The presence of a 3α-ketosteroid oxidoreductase in the rat ventral prostate cytoplasm has been demonstrated. The enzyme was confined to the 105 000 × g supernatant fraction with very little activity in the mitochondrial-microsomal fraction. Addition of NADPH2 was necessary for the enzymatic reaction to proceed. The enzymatic activity was lost when supernatant fractions were dialysed against 0.1 m Tris-HCl buffer, pH 7.4 or when chromatographed by gel filtration using the same buffer. When either L-cysteine, reduced glutathione, 2-mercaptoethanol or EDTA was added to the buffer, the enzymatic activity was preserved. The molecular weight of the enzyme was calculated to be 40 000–50 000. 3H-5α-dihydrotestosterone associates with macromolecules in the 105 000 × g supernatant fraction which are of two molecular sizes (60 000–70 000 and ∼ 200 000). These complexes could not be demonstrated by gel filtration using buffers containing either reduced glutathione, 2-mercaptoethanol or EDTA. By using L-cysteine, the small molecular complex was preserved.

scholarly journals THE EFFECT OF PODOPHYLLOTOXIN ON TISSUE METABOLISM AND ENZYME SYSTEMS

1949 ◽  
Vol 90 (6) ◽  
pp. 525-541 ◽  
Author(s):  
Zelma Baker Miller ◽  
Clarke Davison ◽  
Paul K. Smith
Keyword(s):  
Lymph Nodes ◽  
Rat Brain ◽  
Rat Liver ◽  
Chicken Embryo ◽  
Rat Kidney ◽  
Liver Homogenate ◽  
Rabbit Kidney ◽  
Toxic Dose ◽  
Kidney Homogenate

Podophyllotoxin, 10–3M, inhibits the respiration in vitro of rat lymph nodes, thymus, kidney, tumor, spleen, liver, brain, testis, and chicken embryo. Lymph node and spleen respiration are most sensitive, and the degree of inhibition increases with time. The injection of podophyllotoxin into tumor-bearing mice (20 mg. per kg.) causes a dramatic reduction in the respiration of tumor slices. Within 6 hours, the respiration approaches zero. Inhibition is evident 2 hours after injection of the drug. Spleen respiration is reduced 50 per cent within 6 hours. Kidney and liver respirations remain within normal limits. Marked reductions in the respiration of spleen, lymph nodes, and thymus glands of normal rats are produced by the injection of 15 mg. per kg. Thymus gland is the most sensitive of these three tissues, and its respiration is reduced 66 per cent 24 hours after injection of the drug. The injection of 0.8 microgram podophyllotoxin into the yolk sac of chicken eggs bearing 5 day embryos has no effect on the respiration of the embryo within 8 hours, although this is a sufficiently toxic dose to kill 80 per cent of the embryos (within 24 hours). Kidney respiration in the presence of acetate, glucose, alanine, and glutamate is inhibited to approximately the same degree as in the absence of added substrate. Succinate and pyruvate oxidation by rat kidney slices appear to be less sensitive. Oxidation of acetate and butyrate by rabbit kidney homogenate is more sensitive to podophyllotoxin than oxidation by rabbit kidney homogenate without added substrate. Glucose oxidation by this preparation is not inhibited by 10–3M podophyllotoxin. The anaerobic glycolysis of chicken embryo, rat brain, and rat testis is stimulated by 10–5 and 10–6M podophyllotoxin, and is inhibited by 10–3M. The following enzymes are not inhibited by 10–3M podophyllotoxin: succinoxidase from pigeon breast muscle, choline, xanthine and tyrosine oxidase from rat liver homogenate, and leucine oxidase from Proteus vulgaris; alkaline and acid phosphatase from dog serum; adenosine triphosphatase from rat liver; choline esterase from rat brain homogenate; ribonucleodepolymerase from spleen mince and thymonucleodepolymerase from dog serum. High concentrations of podophyllotoxin do not influence the viscosity and degree of polymerization of thymonucleic acid.

scholarly journals Biosynthesis of cyclopropyl long-chain fatty acids from cyclopropanecarboxylic acid by mammalian tissues in vitro

1968 ◽  
Vol 109 (3) ◽  
pp. 449-455 ◽  
Author(s):  
W. G. Duncombe ◽  
T. J. Rising
Keyword(s):  
Fatty Acids ◽  
Rat Liver ◽  
Liver Homogenate ◽  
Supernatant Fraction ◽  
Long Chain Fatty Acids ◽  
Straight Chain ◽  
Cyclopropanecarboxylic Acid ◽  
Mammalian Tissues ◽  
Chain Fatty Acids

1. Radioactivity from cyclopropane[14C]carboxylic acid is incorporated into fatty acids in vitro by rat and guinea-pig adipose tissue, by rat liver slices and by the supernatant fraction of rat liver homogenate. 2. The labelled acids are different from endogenous straight-chain fatty acids, and evidence is produced that they consist of a cyclopropyl ring in the ω-position, the remainder of the chain being built up from C2 units (not derived from cyclopropanecarboxylic acid) in the normal way via the malonate pathway. 3. It is suggested that these unnatural acids have some metabolic effect related to the hypoglycaemic action of cyclopropanecarboxylic acid.

Cholesterol metabolism and vitamin B6. I. Hepatic cholesterogenesis and pyridoxine deficiency

1969 ◽  
Vol 47 (6) ◽  
pp. 631-635 ◽  
Author(s):  
P. J. Lupien ◽  
C. M. Hinse ◽  
M. Avery
Keyword(s):  
Rat Liver ◽  
High Speed ◽  
Cholesterol Metabolism ◽  
Reductase Activity ◽  
Liver Microsomes ◽  
Liver Homogenate ◽  
Supernatant Fraction ◽  
Liver Cholesterol ◽  
Pyridoxine Deficiency ◽  
Hepatic Cholesterogenesis

Hepatic cholesterogenesis was studied in pair-fed and pyridoxine-deficient rats as well as in rat liver homogenate systems. Crossover of various subcellular components from pair-fed homogenates into pyridoxine-deficient homogenate systems and vice versa was also done.On 8 weeks of pyridoxine deficiency, acetate-14C incorporation rates into liver cholesterol increased by a factor of approximately 10. The same phenomenon was observed with the total liver homogenate systems.Pyridoxine deficiency does not appear to affect HMG-CoA reductase activity of pyridoxine-deficient liver microsomes sufficiently to explain the rapid acetate-1-14C incorporation rates in this same tissue. The activating system(s) responsible for the 10-fold increase in acetate-14C incorporation rates into pyridoxine-deficient rat liver cholesterol appears to be located in the high-speed supernatant fraction. Other subcellular components such as lysosomes and mitochondria are probably implicated to some extent in this phenomenon. The results indicate that vitamin B6 is necessary for normal hepatic cholesterogenesis in the rat.The significance of these findings and the possible relationship between these factors are discussed.

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