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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Archives of toxicology 55 (1984), S. 123-126 
    ISSN: 1432-0738
    Keywords: Rat ; Intestinal cells ; Glucuronidation ; 1-Naphthol ; Glucose ; Fructose ; d-Galactosamine ; Ethanol ; Diethyl ether ; Sorbitol
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Glucuronidation of 1-naphthol was studied in mucosal cells isolated from the rat intestine. Glucuronidation was directly dependent on the supply of extracellular carbohydrates. Basal glucuronidation (ca. 0.3 nmoles/min · mg cell protein) was increased 2- to 3-fold by adding glucose or fructose to the incubation medium. Saturation of glucuroniation was achieved by adding 0.3 mM glucose, while saturation by fructose was not reached at concentrations below 2 mM. No carbohydrate reserves able to support glucuronidation appear to be present in intestinal cells, since no difference in glucuronidation was observed between cells prepared from fasted (18 or 42 h) and control rats. Glucuronidation was decreased by adding d-galactosamine to the incubation medium, but only when extracellular glucose was present. Various chemicals which are known to inhibit glucuronidation in hepatocytes (ethanol, diethyl ether, sorbitol) did not influence the glucuronidation of 1-naphthol in isolated intestinal cells. Only when ethanol was added to mucosal cells in the absence of extracellular glucose was a small decrease in glucuronidation observed.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1749-6632
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Natural Sciences in General
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 343 (1991), S. 330-333 
    ISSN: 1432-1912
    Keywords: Rat isolated perfused kidney ; Flow-dependent renal extraction ; p-Aminohippuric acid ; 1-Naphthol ; Renal clearance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The influence of variation of perfusion flow rate on the renal clearance of p-aminohippuric acid and 1-naphthol was studied with an isolated perfused rat kidney preparation. Kidney functions were well maintained at low perfusion flow rates by the use of a fluorocarbon emulsion to increase the oxygen capacity of the perfusion buffer. Renal extraction of p-aminohippuric acid decreased with increasing perfusion flow. Our data show that at high perfusion flow rates maximal extractable perfusion flow forms only a small part of the total perfusion flow. 1-Naphthol is rapidly metabolized to its glucuronide and sulfate conjugate in the isolated perfused rat kidney. Using PAH as a marker for the maximal extractable perfusion flow, 1-naphthol could be regarded as a high-extraction compound even at high perfusion flow rates. Our results suggest that p-aminohippuric acid clearance, rather than total perfusion flow rate, should be used as the measure of maximal extractable blood flow for the estimation of extraction ratio in the isolated perfused kidney of compounds excreted or metabolized by the proximal tubules.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 0263-6484
    Keywords: Intestine ; isolated epithelial cells ; rat ; enzymic ; vibration ; 3-methylcholanthrene ; O-deethylation ; conjugation ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Two cell isolation procedures, i.e. a scraping/collagenase-treatment and a new vibration procedure in EDTA containing medium, were used to isolate intestinal epithelial cells. In both cell populations the metabolism of 7-ethoxycoumarin and 7-hydroxycoumarin was studied. Moreover, the time course and extent of induction of both steps in the biotransformation were investigated after oral 3-methylcholanthrene pretreatment of the rats. Twenty four hours after 3-methylcholanthrene pretreatment (20 mg kg-1) monooxygenase activity was induced about 6-fold and 2.5-fold when studied with cells of the vibratory and enzymic procedures, respectively. Control 7-ethoxycoumarin deethylase activity and 7-hydroxycoumarin glucuronidation were about the same when comparing both methods for cell-isolation. The formation of glucuronides in cells (both methods) is significantly lowered by 3-MC pretreatment, while sulphation remains unaffected. Results indicate that using enzymic treatment of mucosal scrapings, cell-populations are obtained containing relatively more differentiated (tip) cells. A number of advantages of the new (vibration) method are: better recovery, viability and reproducibility.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 0263-6484
    Keywords: Intestine ; epithelial cells ; rat ; electron microscopy ; O-deethylation ; glucuronidation ; 7-ethoxycoumarin ; 1-naphthol ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Rat intestinal epithelial cells were isolated by EDTA-chelation, combined with gentle shaking (modified Weiser procedure) or with strong longitudinal vibration (Harrison/Webster procedure). Both methods yield large numbers of viable cells and are relatively easy to use. Electronmicroscopical and biochemical data indicate that cell fractions from different levels of the villous region can be obtained only by the modified Weiser procedure. When strong mechanical forces are involved (Harrison-Webster procedure) the villus epithelium is released according to an all-or-nothing process. The biotransformational capacity of cell fractions, obtained from different levels of the villi by the modified Weiser procedure, was investigated. It was shown that the rate of metabolism of 7-ethoxycoumarin and 1-naphthol was substantially higher in lower villous cells than in cells isolated from the upper villous region. O-Deethylation of 7-ethoxycoumarin decreases from 145 ± 13 pmole/min mg cell protein (72 ± 4% conjugated) in lower villous cells to 62 ± 12 pmole/min mg cell protein (37 ± 6% conjugated) in tip cells. Glucuronidation of 1-naphthol decreased from 495 ± 23 pmole/min mg cell protein (lower villous cells) to 137 ± 13 pmole/min mg cell protein (tip cells).
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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