Document Detail

Effect of vitamins C and E on endogenous synthesis of N-nitrosamino acids in humans: precursor-product studies with [15N]nitrate.
MedLine Citation:
PMID:  4063996     Owner:  NLM     Status:  MEDLINE    
The endogenous formation of nitrosoproline (NPRO) following administration of nitrate and proline is reported in ten healthy young adults. There was a relatively constant basal excretion of NPRO, 26 +/- 10 (SD) nmol/day, in excess of amounts found in the diet. This basal synthesis of NPRO was not reduced by ascorbic acid (2 g/day) or alpha-tocopherol (400 mg/day). A significant rise in the excretion of NPRO was observed following the administration of nitrate and proline, ranging from 29 to 318 nmol/24 h with a mean of 100 nmol/24 h. [15N]Nitrate was used as a tracer to study the observed excess excretion of NPRO in urine. The data revealed that urinary NPRO excretion as a result of endogenous synthesis is not totally derived from ingested nitrate as its precursor. The ingestion of ascorbic acid and alpha-tocopherol inhibited the incorporation of [15N]nitrate into NPRO by 81 and 59%, respectively. An additional nitrosamino acid, N-nitrosothiazolidine-4-carboxylic acid, was present in the urine. It was found that N-nitrosothiazolidine-4-carboxylic acid increased 6-fold upon ingestion of nitrate. Ascorbic acid and alpha-tocopherol blocked this nitrate induced synthesis.
D A Wagner; D E Shuker; C Bilmazes; M Obiedzinski; I Baker; V R Young; S R Tannenbaum
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Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Cancer research     Volume:  45     ISSN:  0008-5472     ISO Abbreviation:  Cancer Res.     Publication Date:  1985 Dec 
Date Detail:
Created Date:  1985-12-30     Completed Date:  1985-12-30     Revised Date:  2007-11-14    
Medline Journal Info:
Nlm Unique ID:  2984705R     Medline TA:  Cancer Res     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  6519-22     Citation Subset:  IM    
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MeSH Terms
Ascorbic Acid / pharmacology*
Nitrates / metabolism
Nitrosamines / biosynthesis*
Vitamin E / pharmacology*
Grant Support
1-P01-CA26731-05/CA/NCI NIH HHS
Reg. No./Substance:
0/Nitrates; 0/Nitrosamines; 1406-18-4/Vitamin E; 50-81-7/Ascorbic Acid; 7519-36-0/nitrosoproline

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