Glucocorticoid receptors in the guinea pig

1978 ◽  
Vol 235 (3) ◽  
pp. R115-R120 ◽  
Author(s):  
A. J. Hodgson ◽  
J. W. Funder
Keyword(s):  
Guinea Pig ◽  
Inhibitory Activity ◽  
Guinea Pigs ◽  
Glucocorticoid Receptors ◽  
Metabolizing Enzymes ◽  
Pig Liver ◽  
Liver And Kidney ◽  
Guinea Pig Liver

In cytoplasmic fractions of liver and kidney prepared from adrenalectomized guinea pigs, tritiated dexamethasone ([3H]DM) is bound with a very low affinity (Kd 4 degrees C greater than or equal to 2 X 10(-7) M). By competition studies, the specificity of this binding was shown to be comparable with that for [3H]DM binding to glucocorticoid receptors in other species. In addition, cytoplasmic preparations from guinea pig liver and kidney appear to inhibit the binding of [3H]DM to rat glucocorticoid receptors under a variety of experimentally determined circumstances. It is proposed that such inhibitory activity may reflect a system of [3H]DM sequestration, perhaps by metabolizing enzymes with a high combining power for glucocorticoids. Both low affinity glucocorticoid receptors and avid binding to sites of metabolism may represent additive cellular bases for the apparent corticoresistance of the guinea pig.

scholarly journals Guinea-pig liver tryptophan pyrrolase. Absence of detectable apoenzyme activity and of hormonal induction by cortisol and possible regulation by tryptophan

1974 ◽  
Vol 138 (3) ◽  
pp. 445-451 ◽  
Author(s):  
Abdulla A.-B. Badawy ◽  
Myrddin Evans
Keyword(s):  
Guinea Pig ◽  
Liver Enzyme ◽  
Guinea Pigs ◽  
Actinomycin D ◽  
The Other ◽  
Pig Liver ◽  
Latent Form ◽  
Tryptophan Pyrrolase ◽  
Guinea Pig Liver

1. When assayed in fresh homogenates, guinea-pig liver tryptophan pyrrolase exists only as holoenzyme. It does not respond to agents that activate or inhibit the rat liver enzyme in vitro. Only by aging (for 30min at 5°C) does the guinea-pig enzyme develop a requirement for ascorbate. 2. The guinea-pig liver enzyme is activated by the administration of tryptophan but not cortisol, salicylate, ethanol or 5-aminolaevulinate. 3. The tryptophan enhancement of the guinea-pig liver pyrrolase activity is prevented by 0, 34 and 86% by pretreatment with actinomycin D, cycloheximide or allopurinol respectively. 4. The guinea-pig liver tryptophan pyrrolase is more sensitive to tryptophan administration than is the rat enzyme. On the other hand, the concentrations of tryptophan in sera and livers of guinea pigs are 45–52% less than those in rats. 5. It is suggested that tryptophan may regulate the activity of guinea-pig liver tryptophan pyrrolase by mobilizing a latent form of the enzyme whose primary function is the detoxication of its substrate.

SOME PROPERTIES OF APOFERRITIN ISOLATED FROM GUINEA PIG LIVER

1962 ◽  
Vol 40 (1) ◽  
pp. 983-987 ◽  
Author(s):  
Felix Friedberg
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Guinea Pig ◽  
Amino Acid Composition ◽  
Acid Composition ◽  
Guinea Pigs ◽  
Dicarboxylic Acids ◽  
Acetate Buffer ◽  
Pig Liver ◽  
Guinea Pig Liver

Apoferritin isolated from livers of guinea pigs and characterized by a s°w,20 of 17.7 and a pI of 4.8 (in acetate buffer Γ/2 0.1) was hydrolyzed with 5.7 N HCl for 22 and 44 hours and its amino acid composition determined. The protein appears rich in dicarboxylic acids and in leucine. The content of sulphur-containing amino acids is fairly small.

Osmotic regulation in isolated liver and kidney slices

1960 ◽  
Vol 199 (6) ◽  
pp. 1227-1231 ◽  
Author(s):  
A. G. Swan ◽  
A. T. Miller
Keyword(s):  
Guinea Pig ◽  
Osmotic Pressure ◽  
Kidney Cortex ◽  
Osmotic Regulation ◽  
Sodium Potassium ◽  
Pig Liver ◽  
Kidney Slices ◽  
Liver And Kidney ◽  
Isolated Liver ◽  
Guinea Pig Liver

Slices of guinea pig liver and kidney cortex were incubated under a variety of metabolic and osmotic conditions and the changes in tissue osmotic pressure and in water and electrolyte distribution were measured. The fresh tissues were approximately isotonic with serum, so that swelling was not due to initially hypertonic cell contents. Autolysis was not an important cause of swelling, probably because of leakage of the autolytic products from the cells. Influx of NaCl was sufficient to account for passage of water into the cells. Based on measured fluxes of sodium, potassium and chloride alone, the water of swelling was isotonic or hypertonic but never hypotonic.

Use of coenzymes I and II in interconversion of testosterone and androstenedione

1961 ◽  
Vol 200 (2) ◽  
pp. 348-350 ◽  
Author(s):  
Charles D. Kochakian ◽  
V. S. Raut ◽  
Gordon Kinson
Keyword(s):  
Guinea Pig ◽  
Adult Male ◽  
Reverse Reaction ◽  
Oxidative Process ◽  
Pig Liver ◽  
Liver And Kidney ◽  
Guinea Pig Liver

Adult male guinea pig liver and kidney homogenates were able to utilize triphosphopyridine nucleotide as well as diphosphopyridine nucleotide in the conversion of testosterone and androstenedione and the reduced coenzymes in the reverse reaction. The oxidative process was much more effective than the reductive. The only other metabolite recognized was androsterone found in trace amounts during the reductive reaction.

scholarly journals An oxygenase from guinea-pig liver which catalyses sulphoxidation

1974 ◽  
Vol 143 (3) ◽  
pp. 613-624 ◽  
Author(s):  
Kumaraswamy Prema ◽  
K. P. Gopinathan
Keyword(s):  
Guinea Pig ◽  
Maximal Activity ◽  
Superoxide Anions ◽  
Optimal Conditions ◽  
Metabolizing Enzymes ◽  
Pig Liver ◽  
General Drug ◽  
Liver Homogenates ◽  
Cytochrome P 450 ◽  
Guinea Pig Liver

A mono-oxygenase catalysing the conversion of 2-ethyl-4-thioisonicotinamide (ethionamide) into its sulphoxide was purified from guinea-pig liver homogenates. The enzyme required stoicheiometric amounts of oxygen and NADPH for the sulphoxidation reaction. The purified protein is homogeneous by electrophoretic, antigenic and chromatographic criteria. The enzyme has mol.wt. 85000 and it contains 1g-atom of iron and 1mol of FAD per mol, but not cytochrome P-450. The enzyme shows maximal activity at pH7.4 in a number of different buffer systems and the Km values calculated for the substrate and NADPH are 6.5×10−5m and 2.8×10−5m respectively. The activation energy of the reaction was calculated to be 36kJ/mol. Under optimal conditions, the molecular activity of the enzyme (mol of substrate oxidized/min per mol of enzyme) is calculated to be 2.1. The oxygenase belongs to the class of general drug-metabolizing enzymes and it may act on different compounds which can undergo sulphoxidation. The mechanism of sulphoxidation was shown to be mediated by superoxide anions.

Expression and translation of the growth hormone-receptor gene in the guinea-pig

1992 ◽  
Vol 133 (3) ◽  
pp. 357-362 ◽  
Author(s):  
S. Harvey ◽  
R. A. Fraser
Keyword(s):  
Guinea Pig ◽  
Guinea Pigs ◽  
Plasma Membranes ◽  
Growth Hormone Receptor ◽  
Receptor Gene ◽  
Pig Liver ◽  
Gh Receptor ◽  
Growth Hormone Receptor Gene ◽  
Guinea Pig Liver ◽  
Gh Receptors

ABSTRACT The refractoriness of guinea-pigs to the growth-promoting actions of exogenous GH has been suggested to be due to a deficiency or defect in tissue GH receptors or in GH-receptor gene expression. GH-receptor mRNA was, however, demonstrated by Northern blot analysis and by the polymerase chain reaction in extracts of guinea-pig liver, adipose tissue, brain, hypothalamus and pituitary gland. High-affinity, low-capacity binding sites for radio-labelled ovine GH were also demonstrated on the plasma membranes of guinea-pig liver and were similar to those in rat liver. These results demonstrate that the unresponsiveness of guinea-pigs to exogenous GH is not due to the absence of GH receptors. Journal of Endocrinology (1992) 133, 357–362

(S)-Preferential detoxification of 4-hydroxy-2(E)-nonenal enantiomers by hepatic glutathione S-transferase isoforms in guinea-pigs and rats

2001 ◽  
Vol 355 (1) ◽  
pp. 237-244 ◽  
Author(s):  
Akira HIRATSUKA ◽  
Kouichi TOBITA ◽  
Hiroshi SAITO ◽  
Yasuhiro SAKAMOTO ◽  
Hiroaki NAKANO ◽  
...  
Keyword(s):  
Guinea Pig ◽  
Guinea Pigs ◽  
High Catalytic Activity ◽  
Glutathione S Transferase ◽  
Pig Liver ◽  
Liver Cytosol ◽  
Glutathione S Transferases ◽  
Human Livers ◽  
A Minor ◽  
Guinea Pig Liver

In guinea-pig liver cytosol, racemic 4-hydroxy-2(E)-nonenal (HNE), a reactive and highly toxic product released from biomembranes by lipid peroxidation, was detoxified (S)-preferentially by GSH conjugation mediated by glutathione S-transferases (GSTs) and (R)-preferentially by NAD+-dependent oxidation mediated by aldehyde dehydrogenase (ALDH). The GST-mediated detoxification of the HNE enantiomers proceeded at much higher rates than that mediated by ALDH in guinea-pig liver cytosol. All the major guinea-pig GSTs, A1-1, M1-1, M1-2 and M1-3*, isolated from guinea-pig liver cytosol also catalysed the (S)-preferential conjugation of the HNE enantiomers. The liver and other major tissues of guinea-pigs had no immunologically detectable level of a putative GSTA4-4 orthologue, which exists as a minor GST protein in rat, mouse and human livers and exhibits extremely high catalytic activity towards HNE. All the hepatic rat GSTs, A1-1(2), A1-3, A4-4, M1-1, M1-2 and M2-2, also catalysed the (S)-preferential conjugation of HNE enantiomers.

scholarly journals TISSUE RESPIRATION STUDIES ON NORMAL AND SCORBUTIC GUINEA PIG LIVER AND KIDNEY

1937 ◽  
Vol 120 (1) ◽  
pp. 129-140
Author(s):  
Elmer Stotz ◽  
Carter J. Harrer ◽  
M.O. Schultze ◽  
C.G. King
Keyword(s):  
Guinea Pig ◽  
Tissue Respiration ◽  
Pig Liver ◽  
Liver And Kidney ◽  
Guinea Pig Liver
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