pH-dependent nitration of para-hydroxyphenylacetic acid in the stomach

The major urinary metabolite of nitrotyrosine is 3-nitro-4-hydroxyphenylacetic acid (3-Nitro-HPA). However, recent animal studies have shown that the majority of urinary 3-Nitro-HPA is derived from nitration of endogenous para-hydroxyphenylacetic acid (HPA), a metabolite of tyrosine. One potential s...

Full description

Saved in:
Bibliographic Details
Published in:Free radical biology & medicine 2006-09, Vol.41 (6), p.896-901
Main Authors: Pannala, Ananth S., Mani, Ali R., Rice-Evans, Catherine A., Moore, Kevin P.
Format: Article
Language:English
Subjects:
3-Nitro-4-hydroxyphenylacetic acid
3-Nitrotyrosine
Acrylates - metabolism
Adult
Female
Humans
Hydrogen-Ion Concentration
Kinetics
Male
Middle Aged
Nitrate
Nitrates - metabolism
Nitric Oxide - metabolism
Nitrite
Omeprazole
Phenols - metabolism
Reference Values
Stomach - metabolism
Tyrosine - analogs & derivatives
Tyrosine - metabolism
Tyrosine - urine
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:The major urinary metabolite of nitrotyrosine is 3-nitro-4-hydroxyphenylacetic acid (3-Nitro-HPA). However, recent animal studies have shown that the majority of urinary 3-Nitro-HPA is derived from nitration of endogenous para-hydroxyphenylacetic acid (HPA), a metabolite of tyrosine. One potential site for the formation of 3-Nitro-HPA is the stomach, where nitrous acid is formed by the reaction of nitrite in saliva with gastric acid. The aim of this study was to determine whether there is pH-dependent nitration of salivary para-hydroxyphenylacetic acid or tyrosine, and the effects of dietary nitrate. Healthy volunteers ( n = 18) ingested either a low or high nitrate diet, with and without the administration of omeprazole, a proton pump inhibitor. Urinary 3-Nitro-HPA excretion increased from 197 ± 52 to 319 ± 88 μg/day on switching from a low to a high nitrate diet ( P 
ISSN:0891-5849
1873-4596
DOI:10.1016/j.freeradbiomed.2006.05.010