Kinetics of the uptake and metabolism of 3H-(�) isoprenaline in the rat submaxillary gland

1978 ◽  
Vol 305 (1) ◽  
pp. 51-63 ◽  
Author(s):  
H. Major ◽  
I. Sauerwein ◽  
K. -H. Graefe
Keyword(s):  
Submaxillary Gland ◽  
Kinetics Of ◽  
Uptake And Metabolism

scholarly journals Kinetics of L-Theanine Uptake and Metabolism in Healthy Participants Are Comparable after Ingestion of L-Theanine via Capsules and Green Tea

2012 ◽  
Vol 142 (12) ◽  
pp. 2091-2096 ◽  
Author(s):  
Lisa Scheid ◽  
Sabine Ellinger ◽  
Birgit Alteheld ◽  
Hannes Herholz ◽  
Jörg Ellinger ◽  
...  
Keyword(s):  
Green Tea ◽  
Kinetics Of ◽  
Uptake And Metabolism ◽  
Healthy Participants

Kinetics of Uptake and Metabolism of Atrazine in Model Plant Systems

1997 ◽  
Vol 49 (2) ◽  
pp. 157-163 ◽  
Author(s):  
Muriel Raveton ◽  
Patrick Ravanel ◽  
Anne Marie Serre ◽  
Françoise Nurit ◽  
Michel Tissut
Keyword(s):  
Model Plant ◽  
Kinetics Of Uptake ◽  
Kinetics Of ◽  
Uptake And Metabolism

scholarly journals Effect of halothane on metabolism of 5-hydroxytryptamine by rat lungs perfused in situ

1983 ◽  
Vol 210 (1) ◽  
pp. 157-166 ◽  
Author(s):  
C A Watkins ◽  
S A Wartell ◽  
D E Rannels
Keyword(s):  
Acid Transport ◽  
Rat Lungs ◽  
Saturation Kinetics ◽  
5 Ht Uptake ◽  
Kinetics Of ◽  
Uptake And Metabolism ◽  
Ylacetic Acid ◽  
Made In ◽  
Rate Of Accumulation

The effect of halothane (2-bromo-2-chloro-1,1,1-trifluoroethane) on the uptake of 14C-labelled 5-hydroxytryptamine (5-HT) and its metabolism to 5-hydroxyindol-3-ylacetic acid (5-HIAA) was investigated in rat lungs perfused in situ. The rate of accumulation of 14C-labelled 5-HIAA in the tissue, monitored as an index of 5-HT metabolism, was linear with time, displayed saturation kinetics and remained stable for at least 180 min of perfusion. Exposure of the lungs to halothane (4%) for 60 min reversibly reduced production of 5-HIAA through an increase in the apparent Km for metabolism of the amine from 1.45 to 3.52 microM (P less than 0.001); the anaesthetic had no effect on the Vmax. of the process. The magnitude of the inhibition increased with time of exposure to the anaesthetic. Halothane exposure did not alter the distribution of [3H]sorbitol or [14C]5-HT, pulmonary vascular resistance, levels of ATP or the kinetics of amino acid transport in the tissue. Inhibition of protein synthesis by cycloheximide did not mimic the effect of the anaesthetic. These observations, together with those made in lungs exposed to inhibitors of 5-HT uptake and metabolism, were consistent with a halothane-mediated inhibition of 5-HT uptake, which did not appear to involve non-specific changes in membrane permeability.

Ethanol-Associated Alterations in the Kinetics of Putrescine Uptake and Metabolism by the Regenerating Liver

1992 ◽  
Vol 16 (1) ◽  
pp. 5-10 ◽  
Author(s):  
Anna Mae Diehl ◽  
Shi Qi Yang ◽  
Nesbitt Brown ◽  
Jeff Smith ◽  
David Raiford ◽  
...  
Keyword(s):  
Regenerating Liver ◽  
Kinetics Of ◽  
Uptake And Metabolism

Kinetics of uptake and metabolism by endothelial cell from indicator dilution data

1987 ◽  
Vol 15 (2) ◽  
pp. 201-215 ◽  
Author(s):  
John H. Linehan ◽  
Thomas A. Bronikowski ◽  
Christopher A. Dawson
Keyword(s):  
Endothelial Cell ◽  
Indicator Dilution ◽  
Kinetics Of Uptake ◽  
Kinetics Of ◽  
Uptake And Metabolism

scholarly journals Uptake and metabolism of β-apo-8′-carotenal, β-apo-10′-carotenal, and β-apo-13-carotenone in Caco-2 cells

2019 ◽  
Vol 60 (6) ◽  
pp. 1121-1135 ◽  
Author(s):  
Boluwatiwi O. Durojaye ◽  
Kenneth M. Riedl ◽  
Robert W. Curley ◽  
Earl H. Harrison
Keyword(s):  
Cell Monolayer ◽  
Intestinal Cells ◽  
Limited Information ◽  
Differentiated Cells ◽  
Minor Metabolite ◽  
Tween 40 ◽  
Kinetics Of Uptake ◽  
A Minor ◽  
Kinetics Of ◽  
Uptake And Metabolism

β-Apocarotenoids are eccentric cleavage products of carotenoids formed by chemical and enzymatic oxidations. They occur in foods containing carotenoids and thus might be directly absorbed from the diet. However, there is limited information about their intestinal absorption. The present research examined the kinetics of uptake and metabolism of β-apocarotenoids. Caco-2 cells were grown on 6-well plastic plates until a differentiated cell monolayer was achieved. β-Apocarotenoids were prepared in Tween 40 micelles, delivered to differentiated cells in serum-free medium, and incubated at 37°C for up to 8 h. There was rapid uptake of β-apo-8′-carotenal into cells, and β-apo-8′-carotenal was largely converted to β-apo-8′-carotenoic acid and a minor metabolite that we identified as 5,6-epoxy-β-apo-8′-carotenol. There was also rapid uptake of β-apo-10′-carotenal into cells, and β-apo-10′-carotenal was converted into a major metabolite identified as 5,6-epoxy-β-apo-10′-carotenol and a minor metabolite that is likely a dihydro-β-apo-10′-carotenol. Finally, there was rapid cellular uptake of β-apo-13-carotenone, and this compound was extensively degraded. These results suggest that dietary β-apocarotenals are extensively metabolized in intestinal cells via pathways similar to the metabolism of retinal. Thus, they are likely not absorbed directly from the diet.

scholarly journals In Vivo Regulation of DOPA Decarboxylase by Dopamine Receptors in Rat Brain

1997 ◽  
Vol 17 (11) ◽  
pp. 1254-1260 ◽  
Author(s):  
Paul Cumming ◽  
Ariel Ase ◽  
Christine Laliberté ◽  
Hiroto Kuwabara ◽  
Albert Gjedde
Keyword(s):  
Monoamine Oxidase ◽  
Receptor Antagonist ◽  
Receptor Agonist ◽  
Dopa Decarboxylase ◽  
Olfactory Tubercle ◽  
Da Receptors ◽  
Mao Activity ◽  
Kinetics Of ◽  
Uptake And Metabolism

To test the hypothesis that dopamine (DA) receptors influence cerebral DOPA-decarboxylase (DDC) activity in vivo, we used HPLC to measure the kinetics of the cerebral uptake and metabolism of [3H]DOPA in carbidopa-treated rats, and in rats also treated acutely with a DA receptor antagonist (flupenthixol, 2 mg/kg, intraperitoneally) or a DA receptor agonist (apomorphine, 200 μg/g, subcutaneously). The unidirectional blood-brain clearance of [3H]DOPA (K1DOPA, 0.030 mL g−1 min−1) increased by 50% after flupenthixol. The magnitudes of the relative DDC activity (k3DOPA) in striatum (0.20 min−1), olfactory tubercle (0.11 min−1), and hypothalamus (0.15 min−1) of carbidopa-treated rats were doubled with flupenthixol, but cortical DDC activity was unaffected (0.02 min−1). Apomorphine reduced the magnitude of k3DOPA in striatum by 20%. The rate constant for catabolism of [3H]DA formed in brain (k7′, monoamine oxidase [MAO] activity), which ranged from 0.025 min−1 in striatum to 0.08 min−1 in hypothalamus of carbidopa-treated rats, globally increased 2- to 4-fold after flupenthixol, and decreased to 0.003 min−1 in striatum after apomorphine. These in vivo results confirm the claim that acute blockade of DA receptors with flupenthixol stimulates the synthesis of [3H]DA from [3H]DOPA, and that this [3H]DA is subject to accelerated catabolism. Conversely, activation of the DA receptors with apomorphine inhibits DDC activity and DA catabolism.

Direct observations of radiation-enhanced transformations in glass

1983 ◽  
Vol 41 ◽  
pp. 354-355
Author(s):  
J. F. DeNatale ◽  
D. G. Howitt
Keyword(s):  
Glass Matrix ◽  
Diffusion Mechanism ◽  
Bubble Formation ◽  
Silicate Glasses ◽  
Phase Decomposition ◽  
Direct Observations ◽  
Thin Foils ◽  
Oxygen Bubble ◽  
Electron Energy Loss ◽  
Kinetics Of

The electron irradiation of silicate glasses containing metal cations produces various types of phase separation and decomposition which includes oxygen bubble formation at intermediate temperatures figure I. The kinetics of bubble formation are too rapid to be accounted for by oxygen diffusion but the behavior is consistent with a cation diffusion mechanism if the amount of oxygen in the bubble is not significantly different from that in the same volume of silicate glass. The formation of oxygen bubbles is often accompanied by precipitation of crystalline phases and/or amorphous phase decomposition in the regions between the bubbles and the detection of differences in oxygen concentration between the bubble and matrix by electron energy loss spectroscopy cannot be discerned (figure 2) even when the bubble occupies the majority of the foil depth.The oxygen bubbles are stable, even in the thin foils, months after irradiation and if van der Waals behavior of the interior gas is assumed an oxygen pressure of about 4000 atmospheres must be sustained for a 100 bubble if the surface tension with the glass matrix is to balance against it at intermediate temperatures.

Irradiation behavior of pyrolytic silicon carbide

1983 ◽  
Vol 41 ◽  
pp. 72-73
Author(s):  
R. J. Lauf
Keyword(s):  
Silicon Carbide ◽  
Fission Products ◽  
Thermodynamics And Kinetics ◽  
Neutron Fluences ◽  
Fuel Particles ◽  
Sic Coatings ◽  
Irradiation Behavior ◽  
Kinetics Of ◽  
Htgr Fuel

Fuel particles for the High-Temperature Gas-Cooled Reactor (HTGR) contain a layer of pyrolytic silicon carbide to act as a miniature pressure vessel and primary fission product barrier. Optimization of the SiC with respect to fuel performance involves four areas of study: (a) characterization of as-deposited SiC coatings; (b) thermodynamics and kinetics of chemical reactions between SiC and fission products; (c) irradiation behavior of SiC in the absence of fission products; and (d) combined effects of irradiation and fission products. This paper reports the behavior of SiC deposited on inert microspheres and irradiated to fast neutron fluences typical of HTGR fuel at end-of-life.

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