scholarly journals The distribution of l-asparagine synthetase in the principal organs of several mammalian and avian species

1974 ◽  
Vol 142 (1) ◽  
pp. 27-35 ◽  
Author(s):  
Harry A. Milman ◽  
David A. Cooney
Keyword(s):  
Guinea Pig ◽  
Mouse Liver ◽  
Avian Species ◽  
Asparagine Synthetase ◽  
Rapid Rate ◽  
Radiometric Assay ◽  
High Concentrations

A survey was conducted of the distribution of l-asparagine synthetase and of l-asparaginase in the principal organs of representative mammals and birds. Although a radiometric assay was used as a routine, several additional criteria, including enzymic and chromatographic ones, were used to verify that the product of the synthetase was l-asparagine. Recoveries of exogenous l-asparagine were assessed in the presence of a number of mouse organs and found to be about 85%. In addition, evidence is presented for the existence in mouse liver of a thermolabile activity capable of destroying l-asparagine and stimulated by high concentrations of NH4+ ions. Of the organs surveyed, pancreas was generally found to synthesize l-asparagine at the most rapid rate, whereas extracts of liver catalysed the decomposition of this amide at the greatest velocity. Of the species studied, guinea pig had the highest activities of pancreatic l-asparagine synthetase and also of hepatic l-asparaginase. The pancreas of mouse and ox also were good sources of l-asparagine synthetase.

Hepatic uptake of intact glutathione S-conjugate, inhibition by organic anions, and sinusoidal catabolism

1993 ◽  
Vol 265 (3) ◽  
pp. G547-G554
Author(s):  
C. A. Hinchman ◽  
A. T. Truong ◽  
N. Ballatori
Keyword(s):  
Guinea Pig ◽  
Rat Liver ◽  
Marked Decrease ◽  
Hepatic Uptake ◽  
Half Time ◽  
High Concentrations ◽  
Rat Livers ◽  
Dose Dependent ◽  
Uptake And Metabolism ◽  
Guinea Pig Liver

To identify potential mechanisms for hepatic removal of circulating glutathione (GSH) conjugates, uptake and metabolism of S-2,4-dinitrophenylglutathione (DNP-SG) were examined in isolated perfused livers from rat and guinea pig. Guinea pig livers perfused with 5 mumol of DNP-SG in a recirculating system (50 microM initial concn) rapidly cleared the conjugate from the perfusate (half time 3.7 min), whereas clearance was considerably slower in rat liver (half time 35 min). Disappearance of DNP-SG from the perfusate was accompanied by a simultaneous appearance of DNP-SG and its metabolites in bile. Addition of acivicin, an inhibitor of gamma-glutamyltransferase (gamma-GT), to the perfusate resulted in a marked decrease in DNP-SG clearance by guinea pig liver but had no effect in rat liver, suggesting that in the guinea pig this process is largely dependent on sinusoidal gamma-GT activity. However, even in the presence of acivicin, rat and guinea pig livers removed nearly one-half of the administered DNP-SG from the recirculating perfusate over 30 min. High concentrations of DNP-SG were found in bile (up to 3.7 mM), indicating that the liver is capable of transporting the intact conjugate from the circulation. When rat livers were perfused with higher concentrations of DNP-SG (100 and 250 microM), biliary excretion of DNP-SG increased dose dependently, with concentrations in bile reaching 10 mM at the higher dose. This was accompanied by a dose-dependent choleresis.(ABSTRACT TRUNCATED AT 250 WORDS)

The release of slow-reacting substance of anaphylaxis from guinea pig lung: effects of calcium antagonists

1985 ◽  
Vol 63 (1) ◽  
pp. 23-29 ◽  
Author(s):  
Melissa A. Damiano ◽  
Edward J. Barbieri
Keyword(s):  
Guinea Pig ◽  
Intracellular Calcium ◽  
Lung Tissue ◽  
Calcium Antagonists ◽  
Lung Parenchyma ◽  
Free Medium ◽  
Bicarbonate Buffer ◽  
Normal Medium ◽  
Voltage Dependent ◽  
High Concentrations

The effects of three calcium antagonists, verapamil, lanthanum, and 8-(N,N-diethylamino)octyl-3,4,5-trimethoxybenzoate (TMB-8) were studied on the release of slow-reacting substance of anaphylaxis (SRS-A) from ovalbumin-sensitized chopped guinea pig lung parenchyma in calcium-containing and calcium-free media. The SRS-A levels (mean ± SEM) obtained from tissues incubated in normal and calcium-free Krebs–bicarbonate buffer were 51 ± 8 (N = 19) and 21 ± 4 (N = 14) U/mL, respectively. TMB-8 (0.1–10 μM) a reported intracellular calcium antagonist, reduced antigen-stimulated SRS-A release from lung tissue incubated in calcium-containing, but not calcium-free, medium; A23187-induced SRS-A release from normal guinea pig lung was not significantly altered by TMB-8 at concentrations up to 10 μM. Verapamil and lanthanum consistently reduced SRS-A release only at high concentrations (100 μM and 1 mM, respectively). The quantities of SRS-A released from lung tissue incubated in the presence of verapamil in normal medium were similar to those obtained in calcium-free medium. Tissues incubated in the presence of potassium chloride (60 and 100 mM) did not release significant quantities of SRS-A, and release which did occur was not blocked by verapamil, suggesting that antigen-induced SRS-A release is not dependent on membrane depolarization and that verapamil was not exerting inhibition via blockade of voltage-dependent calcium channels. These data suggest that although intracellular calcium is important for the regulation of SRS-A secretion from guinea pig lung tissue, extracellular calcium is necessary for optimal release of SRS-A.

EFFECTS OF CATIONS ON SUGAR ABSORPTION BY ISOLATED SURVIVING GUINEA PIG INTESTINE

1958 ◽  
Vol 36 (3) ◽  
pp. 347-362 ◽  
Author(s):  
E. Riklis ◽  
J. H. Quastel
Keyword(s):  
Guinea Pig ◽  
Glucose Transport ◽  
Active Transport ◽  
Glucose Absorption ◽  
Ion Concentration ◽  
Potassium Ions ◽  
Magnesium Ions ◽  
Sugar Absorption ◽  
Rate Of Absorption ◽  
High Concentrations

The rate of absorption of glucose from isolated surviving guinea pig intestine increases with increase of the concentration of glucose in the lumen until a maximum rate is obtained. The relation between absorption rate of glucose and initial glucose concentration conforms to an equation of the Michaelis–Menten type. The apparent Km(half saturation concentration) is 7 × 10−3M. Increase of the concentration of potassium ions in the Ringer–bicarbonate solution bathing the intestine leads to an increase of the rate of glucose absorption, this being most marked with 15.6 meq./liter K+and 14 mM glucose. No such stimulating action of potassium ions is observed on glucose absorption under anaerobic conditions. The effect of increased potassium ion concentration is to accelerate the rate of transport found with low concentrations of glucose to the maximum value found with high concentrations of the sugar. Sodium ions must be present for glucose absorption to take place and omission of magnesium ions from a Ringer–bicarbonate solution, containing 15.6 meq./liter K+, brings about a decreased rate of active glucose transport. Magnesium ions are necessary for the stimulated rate of glucose absorption obtained in the presence of potassium ions. The presence of ammonium ions decreases the rate of glucose absorption. Potassium ions may be effectively replaced by rubidium ions for stimulation of glucose transport. Cesium ions do not activate. The proportion of glucose to fructose appearing in the serosal solution, when fructose is absorbed from the mucosal solution, depends on the concentration of fructose present. The proportion may be as high as 9:1 with low (7 mM) fructose concentrations; it decreases with increasing fructose concentrations. The active transport of fructose, as demonstrated by the conversion of fructose in the isolated surviving guinea pig intestine, is enhanced by the presence of potassium ions (15.6 meq./liter). The rate of transport of fructose itself is unaffected by potassium. Using radioactive glucose and fructose, it is shown that the total amount of sugar transferred through the intestine as estimated by the radioactivity appearing in the serosal solution is approximately that calculated from chemical analyses. Potassium ions have no activating action on the transport of sugars such as sorbose, mannose, and D-glucosamine, but have a marked effect on galactose transport. The results support the conclusion that potassium ions do not influence active transport of glucose, fructose, and galactose by a change of intestinal permeability to these sugars, but do so by affecting a specific phase involved in the mechanism of active transport of sugars. The presence of L-glutamine stimulates active transport of glucose, whereas that of L-glutamate tends to diminish it.

scholarly journals Identity and Proliferation of Small Lymphocyte Precursors in Cultures of Lymphocyte-rich Fractions of Guinea Pig Bone Marrow

Blood ◽  
1971 ◽  
Vol 37 (1) ◽  
pp. 73-86 ◽  
Author(s):  
Y. YOSHIDA ◽  
D. G. OSMOND
Keyword(s):  
Bone Marrow ◽  
Guinea Pig ◽  
Lymphoid Cells ◽  
Short Term ◽  
Small Lymphocyte ◽  
Undifferentiated Cells ◽  
The Mean ◽  
High Concentrations ◽  
Transitional Cells

Abstract Radioautography with 3H-thymidine was used to examine the proliferative activity of bone marrow lymphoid cells and to identify the precursor cells of small lymphocytes in short-term cultures of lymphocyte-rich marrow fractions. High concentrations of small lymphocytes (nuclear diameters less than 8.0 µ in smears) together with large lymphoid ("transitional") cells (nuclear diameters greater than 8.0 µ) were separated from suspensions of guinea pig bone marrow by centrifugation in linear sucrose-serum density gradients. When such lymphocyte-rich marrow fractions were cultured in vitro the labeling and mitotic indices following either continuous or terminal exposure to 3H-thymidine indicated that the large lymphoid cells were confined mainly to the pre-DNA-synthetic (G1) and early DNA-synthetic (S) phases at first, but proceeded subsequently through S phase and mitosis. From these data tentative values were derived for the in vitro duration of G1 (12 hours) and S (13.7 hours). Further cultures were followed radioautographically after a 1-hour pulse of 3H-thymidine at 6-7 hours of culture. The absolute numbers of labeled large lymphoid cells declined during the subsequent 21 hours but, simultaneously, labeled small lymphocytes appeared and increased progressively in absolute numbers to 44.4 ± 8.1 per cent of the initial numbers of labeled large lymphoid cells. The mean grain count of labeled small lymphocytes was half that of the initially labeled large lymphoid cells. Very few labeled undifferentiated cells other than large lymphoid cells were observed. The results demonstrate that lymphocyte-rich marrow fractions are capable of sustaining the production of small lymphocytes in short-term cultures and that the immediate precursors of marrow small lymphocytes are contained within a population of large lymphoid cells.

scholarly journals Adenosine 3':5'-cyclic monophosphate-dependence of protein kinase isoenzymes from mouse liver

1976 ◽  
Vol 157 (1) ◽  
pp. 117-126 ◽  
Author(s):  
P M Ueland ◽  
S O Døskeland
Keyword(s):  
Protein Kinase ◽  
Cyclic Amp ◽  
Mouse Liver ◽  
Deae Cellulose ◽  
Maximal Activity ◽  
Close Correlation ◽  
Histone Phosphorylation ◽  
Heat Stable ◽  
Dependent Protein ◽  
High Concentrations

Conditions influencing the cyclic AMP-dependence of protein kinase (ATP-protein phosphotransferase, EC 2.7.1.37) during the phosphorylation of histone were studied. Protein kinase from mouse liver cytosol and the two isoenzymes [PK (protein kinase) I and PK II] isolated from the cytosol by DEAE-cellulose chromatography were tested. A relation between concentration of enzyme and cyclic AMP-dependence was observed for both isoenzymes. Moderate dilution of isoenzyme PK II decreased the stimulation of the enzyme by cyclic AMP. Isoenzyme PK I could be diluted 200 times more than isoenzyme PK II before the same decrease in cyclic AMP-dependence appeared. Long-term incubation with high concentrations of histone increased the activity in the absence of cyclic AMP relative to the activity in the presence of the nucleotide. This was more pronounced for isoenzyme PK II than for isoenzyme PK I. The cyclic AMP concentration needed to give half-maximal binding of the nucleotide was the same as the cyclic AMP concentration (Ka) at which the protein kinase had 50% of its maximal activity. The close correlation between binding and activation is also found in the presence of KCl, which increased the apparent activation constant (Ka) for cyclic AMP. With increasing [KCl], a progressively higher proportion of the histone phosphorylation observed in cytosol was due to cyclic AMP-independent (casein) kinases, leading to an overestimation of the degree of activation of the cyclic AMP-dependent protein kinases present. The relative contributions of cyclic AMP-dependent and -independent kinases to histone phosphorylation at different ionic strengths was determined by use of heat-stable inhibitor and phospho-cellulose chromatography.

INCORPORATION OF INORGANIC P32INTO PHOSPHOLIPIDS OF BRAIN SLICES: EFFECT OF CERTAIN TRANQUILLIZING DRUGS

1963 ◽  
Vol 41 (1) ◽  
pp. 1155-1162 ◽  
Author(s):  
W. L. Magee ◽  
R. J. Rossiter
Keyword(s):  
Methylene Blue ◽  
Guinea Pig ◽  
Aerobic Glycolysis ◽  
Brain Slices ◽  
Inorganic P ◽  
Pig Brain ◽  
Low Concentrations ◽  
High Concentrations ◽  
Derivatives Of ◽  
Guinea Pig Brain

Promazine, promethazine, tetrameprazine, and WY 1172, four tranquillizing drugs that are derivatives of phenothiazine, resembled chlorpromazine in that when they were added in a concentration of 0.1 mM to slices of guinea pig brain respiring in a suitable medium they stimulated the incorporation of inorganic P32into the phospholipids of the slices. With one of the drugs, promethazine, this concentration of 0.1 mM was found to cause no significant increase in respiration, in aerobic glycolysis, or in the concentration of phosphocreatine. In higher concentrations (1.0 mM), all of the compounds inhibited the labelling of phospholipid. Promethazine caused a reduction in respiration and in the concentration of phosphocreatine, accompanied by an increase in aerobic glycolysis. Methylene blue, a derivative of phenothiazine with no reported tranquillizing properties, did not stimulate the labelling of phospholipid in brain slices. Azacyclonol, pipradrol, and mepazine, drugs that are derivatives of piperidine, also stimulated phospholipid labelling in low concentrations and inhibited the labelling at higher concentrations. Piperidine and benzhydrol, the two components from which azacyclonol is derived, did not stimulate phospholipid labelling at the concentration which was most effective for azacyclonol. Low concentrations of benzhydrol, however, caused a slight stimulation. Meprobamate and phenaglycodol, two other compounds with reputed tranquillizing action, had either little or no effect. Most of the substances tested inhibited phospholipid labelling when they were added in sufficiently high concentrations.

scholarly journals Membranes and bile formation. Composition of several mammalian biles and their membrane-damaging properties

1979 ◽  
Vol 178 (1) ◽  
pp. 201-208 ◽  
Author(s):  
R Coleman ◽  
S Iqbal ◽  
P P Godfrey ◽  
D Billington
Keyword(s):  
Guinea Pig ◽  
Bile Salts ◽  
Cell Damage ◽  
Membrane Damage ◽  
Total Content ◽  
Hepatic Cell ◽  
Membrane Composition ◽  
Bile Formation ◽  
Composition And Structure ◽  
High Concentrations

The total content and profile of bile salts and phospholipids are reported for several mammalian biles. Rabbit and guinea-pig biles are characterized by high proportions of conjugated dihydroxy bile salts with respect to trihydroxy bile salts, but contain relatively little phospholipid. Both rabbit and guinea-pig biles exhibit little evidence of hepatic cell damage, even though they are able to cause membrane damage (as evidenced by lysis of human erythrocytes) at low (2–3 mM) concentrations of bile salts; this lytic behaviour is also a property of their predominant bile salts. Addition of phosphatidylcholine to the bile or bile salt is able to decrease the lytic behaviour. Perhaps the most significant observation is that these biles, and their predominant bile salts, are dramatically less lytic towards sheep erythrocytes, indicating that some factor(s) in membrane composition and structure may partly explain the resistance of membranes of the biliary tract to the presence of high concentrations of potentially membrane-damaging bile salts.

Platelet-activating factor: lack of direct action on guinea pig myocardium and possible transmitter release from cardiac sympathetic nerve endings at high concentrations

1989 ◽  
Vol 67 (6) ◽  
pp. 669-674 ◽  
Author(s):  
Koki Shigenobu ◽  
Tatsuya Mori ◽  
Katsuo Kamata ◽  
Yutaka Kasuya
Keyword(s):  
Guinea Pig ◽  
Action Potential ◽  
Sympathetic Nerve ◽  
Transmitter Release ◽  
Platelet Activating Factor ◽  
Nerve Endings ◽  
Slow Response ◽  
Ca Current ◽  
Cardiac Action ◽  
High Concentrations

Microelectrode and mechanical studies were performed with isolated guinea pig myocardium (right ventricular free walls and papillary muscles) to examine the effects of platelet-activating factor (PAF) and lysophosphatidylcholine (LPC). Low concentrations of PAF (10−8 to 10−6 M, a range equivalent to the blood concentrations that produce marked hypotension in vivo) had no effects on action potential configuration and contractile force. High concentrations (10−5 to 10−4 M) of PAF and LPC per se elicited slow response action potentials with concomitant contraction (restored contraction) in the myocardium depolarized with elevated K+ (25 mM); they also augmented slow responses and restored contractions produced by a low concentration of isoproterenol (10−8 M). Although these results suggested there was an increase in slow Ca current, the slow responses and restored contractions thus produced were greatly suppressed or abolished by the addition of a β-adrenoceptor blocking agent, sotalol (10−5 M), and by pretreatment with reserpine (5 mg/kg i.p., 24 h prior). In accordance with our previous conclusions, the present results suggest that direct cardiac action is not involved in the mechanisms of hypotension produced by PAF. It was also shown that high concentrations of PAF and LPC may act nonspecifically as amphiphilic compounds to induce transmitter release from sympathetic nerve endings, which may in turn augment the Ca current channels in the myocardial cell membrane.Key words: platelet-activating factor, cardiac action potential, slow response, Ca2+ channel, sympathetic nerve ending.

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