Document Detail

Formation of N-nitrosoiminodialkanoic acids and their unsuitability as biological monitors for endogenous nitrosation of dipeptides.
MedLine Citation:
PMID:  3742725     Owner:  NLM     Status:  MEDLINE    
Nitrosation of dipeptides which do not contain imino acids leads to rearrangement and the formation of N-nitrosoiminodialkanoic acids. The optimum conditions for the nitrosation of dipeptides in buffer solutions occur at pH 2.0 (0.8-3.2% yield) and are not significantly catalysed by thiocyanate. In vitro nitrosation in gastric juice resulted in a lower yield. It was demonstrated that under normal gastric conditions, a maximum yield of 0.1 mumol total N-nitrosoiminodialkanoic acids/0.1 mol dipeptide would occur, 0.1 mol representing a typical dietary intake of dipeptide. This corresponds to a total concentration of approximately 20 micrograms/l N-nitrosoiminodialkanoic acids over a 24 h period. However, this figure may be significantly altered due to the fluctuation of nitrosation catalysts and inhibitors in gastric juice. Further studies showed that N-nitrosoiminodialkanoic acids are quantitatively excreted in urine when fed by gavage to rats. However, co-administration of the precursor dipeptide and nitrite resulted in negligible in vivo formation. The presence of N-nitrosoiminodialkanoic acids in normal human urine was not detected. Thus it was concluded that the monitoring of N-nitrosoiminodialkanoic acids in human urine is not a suitable method for biological monitoring of the endogenous nitrosation of dipeptides.
A R Tricker; R Preussmann
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Carcinogenesis     Volume:  7     ISSN:  0143-3334     ISO Abbreviation:  Carcinogenesis     Publication Date:  1986 Sep 
Date Detail:
Created Date:  1986-10-17     Completed Date:  1986-10-17     Revised Date:  2004-11-17    
Medline Journal Info:
Nlm Unique ID:  8008055     Medline TA:  Carcinogenesis     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  1523-6     Citation Subset:  IM    
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MeSH Terms
Dipeptides / metabolism*
Gastric Juice / metabolism
Hydrogen-Ion Concentration
Monitoring, Physiologic / methods*
Nitrates / pharmacology
Nitroso Compounds / analysis,  metabolism*
Rats, Inbred Strains
Sodium Nitrite / pharmacology
Reg. No./Substance:
0/Dipeptides; 0/Nitrates; 0/Nitroso Compounds; 7631-99-4/sodium nitrate; 7632-00-0/Sodium Nitrite

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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