Library

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    ISSN: 1432-0738
    Keywords: Chenodeoxycholic acid ; Chimpanzee ; Conjugation ; Lithocholic acid ; Sulfation ; Toxicity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Um im Schimpansen die hepatische Biotransformation der primären Gallensäure Chenodeoxycholsäure und deren wichtigstem bakteriellen Metaboliten, Lithocholsäure zu charakterisieren, wurde ein Gemisch aus Spurenmengen von14C-Lithocholsäure und3H-Chenodeoxycholsäure intravenös in zwei Tiere mit Gallenfistel injiziert. Die chemische Form der Radioaktivität, die in der Galle erschien, wurde dünnschichtchromatographisch ermittelt. Etwa 80% der Chenodeoxycholsäure und 70% der Lithocholsäure wurden innerhalb von 90 min ausgeschieden. Die Chenodeoxycholsäure war vollständig konjugiert und erschien vorwiegend als Chenyltaurin (52%) und Chenylglycin (37%). 11% erschienen in einer Form, die bisher nicht identifiziert wurde. Lithocholsäure wurde vollständig als Taurin- und Glycinkonjugat in die Galle eliminiert; der größte Teil (63%) war zusätzlich sulfatiert. Die Sulfatierung nahm stetig mit der Zeit zu und Lithocholylglycine wurde stärker sulfatiert als Lithocholyltaurin. Wir schließen aus diesen Befunden, daß der Schimpanse mit dem Menschen vergleichbar ist, indem er Lithocholsäure effektiv sulfatiert. Dadurch unterscheidet sich der Schimpanse vom Rhesusaffe und Baboon, die die Lithocholsäure nur in geringem Maße sulfatieren. Jedoch unterscheidet sich der Schimpanse auch vom Menschen und ähnelt dem Rhesusaffen und dem Baboon, indem er Gallensäure vorwiegend mit Taurin konjugiert. Die Ergebnisse lassen den Schluß zu, daß die Hepatotoxizität, die im Rhesusaffe und Baboon durch Chenodeoxycholat hervorgerufen wird, und auf eine geringe Sulfatierung der Lithocholsäure zurückgeführt wird, beim Schimpansen nicht bestehen sollte.
    Notes: Abstract To characterize the hepatic biotransformation in the chimpanzee of the primary bile acid chenodeoxycholic acid (chenic) and its major bacterial metabolite lithocholic acid (lithocholic) a mixture of tracer amounts of14C-lithocholic and3H-chenic was injected intravenously into two animals with a bile fistula; the chemical form of radioactivity appearing in bile was inferred using thin layer chromatography. About 80% of chenic, and 70% of lithocholic was recovered in 90 min. Chenic was completely conjugated in bile, appearing predominantly as chenyltaurine (52%) and chenylglycine (37%). An unidentified conjugate (about 11%) was also found. Lithocholic was excreted completely as taurine and glycine conjugates, but the majority (63%) of conjugates was sulfated. Sulfation increased progressively with time, and lithocholylglycine was sulfated more than lithocholyltaurine. We conclude that the chimpanzee is similar to man in that the secondary bile acid lithocholic is efficiently sulfated. The chimpanzee thus differs from the baboon and rhesus monkey which sulfate lithocholic poorly. However, the chimpanzee differs from man and is similar to the baboon and rhesus monkey in showing preferential conjugation of bile acids with taurine. The results imply that hepatotoxicity caused by chenic, which is well documented in the rhesus monkey and baboon and has been related to defective lithocholic sulfation, should not occur in the chimpanzee.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Archives of toxicology 46 (1980), S. 31-40 
    ISSN: 1432-0738
    Keywords: Ames test ; Plate incorporation assay ; Salmonella/microsome test ; Test procedure ; False negatives ; False positives
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract This in vitro mutagenicity test system comprises five different strains of S. typhimurium as target cells with the rat liver S-9 fraction and appropriate co-factors for metabolic activation of the chemical tested. The bacterial tester strains detect both mutations induced by base pair substitutions and intercalation (frame shift mutations). Usually 108–109 cells of an overnight culture or an exponentially growing culture are incubated for 2–3 days with a mixture of S-9, co-factors, soft agar and the chemical on histidine-deficient agar. The S-9 fraction is obtained from the livers of rats pretreated with 500 mg/kg chlorinated biphenyls (Clophen A-50, Aroclor 1254) to obtain high metabolic activity. For reproducibility it is essential to standardize metabolic activity and protein content of the S-9 and to use three different concentrations thereof in the test system. Since solvents inhibit metabolic activation of the chemicals they must not exceed 4% of the final 2.6 ml incubate. Several independent studies have shown that between 85 and 93% of chemical carcinogens are mutagens in the test. Regarding extrapolation to man one has to consider that the test is preferentially adapted for metabolic activation of the chemicals, whereas inactivation processes are absent or are less active than in vivo. Thus, the test provides qualitative rather than quantitative information on mutagenic effects of a chemical.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...