PMID- 10997917
OWN - NLM
STAT- MEDLINE
DCOM- 20001030
LR  - 20171213
IS  - 1931-857X (Print)
IS  - 1522-1466 (Linking)
VI  - 279
IP  - 4
DP  - 2000 Oct
TI  - Effects of homocysteine on endothelial nitric oxide production.
PG  - F671-8
AB  - Hyperhomocysteinemia (HHCy) is an independent and graded cardiovascular risk 
      factor. HHCy is prevalent in patients with chronic renal failure, contributing to 
      the increased mortality rate. Controversy exists as to the effects of HHCy on 
      nitric oxide (NO) production: it has been shown that HHCy both increases and 
      suppresses it. We addressed this problem by using amperometric electrochemical NO 
      detection with a porphyrinic microelectrode to study responses of endothelial 
      cells incubated with homocysteine (Hcy) to the stimulation with bradykinin, 
      calcium ionophore, or L-arginine. Twenty-four-hour preincubation with Hcy (10, 
      20, and 50 microM) resulted in a gradual decline in responsiveness of endothelial 
      cells to the above stimuli. Hcy did not affect the expression of endothelial 
      nitric oxide synthase (eNOS), but it stimulated formation of superoxide anions, 
      as judged by fluorescence of dichlorofluorescein, and peroxynitrite, as detected 
      by using immunoprecipitation and immunoblotting of proteins modified by tyrosine 
      nitration. Hcy did not directly affect the ability of recombinant eNOS to 
      generate NO, but oxidation of sulfhydryl groups in eNOS reduced its NO-generating 
      activity. Addition of 5-methyltetrahydrofolate restored NO responses to all 
      agonists tested but affected neither the expression of the enzyme nor formation 
      of nitrotyrosine-modified proteins. In addition, a scavenger of peroxynitrite or 
      a cell-permeant superoxide dismutase mimetic reversed the Hcy-induced suppression 
      of NO production by endothelial cells. In conclusion, electrochemical detection 
      of NO release from cultured endothelial cells demonstrated that concentrations of 
      Hcy >20 microM produce a significant indirect suppression of eNOS activity 
      without any discernible effects on its expression. Folates, superoxide ions, and 
      peroxynitrite scavengers restore the NO-generating activity to eNOS, collectively 
      suggesting that cellular redox state plays an important role in HCy-suppressed 
      NO-generating function of this enzyme.
FAU - Zhang, X
AU  - Zhang X
AD  - Departments of Medicine and Physiology, State University of New York, Stony 
      Brook, New York 11794-8152, USA.
FAU - Li, H
AU  - Li H
FAU - Jin, H
AU  - Jin H
FAU - Ebin, Z
AU  - Ebin Z
FAU - Brodsky, S
AU  - Brodsky S
FAU - Goligorsky, M S
AU  - Goligorsky MS
LA  - eng
GR  - DK45462/DK/NIDDK NIH HHS/United States
GR  - DK52783/DK/NIDDK NIH HHS/United States
PT  - Journal Article
PT  - Research Support, U.S. Gov't, P.H.S.
PL  - United States
TA  - Am J Physiol Renal Physiol
JT  - American journal of physiology. Renal physiology
JID - 100901990
RN  - 0 (Free Radical Scavengers)
RN  - 0 (Nitrates)
RN  - 0 (Reactive Oxygen Species)
RN  - 0 (Recombinant Proteins)
RN  - 0LVT1QZ0BA (Homocysteine)
RN  - 11062-77-4 (Superoxides)
RN  - 26404-66-0 (peroxynitric acid)
RN  - 31C4KY9ESH (Nitric Oxide)
RN  - 3604-79-3 (3-nitrotyrosine)
RN  - 37H9VM9WZL (Calcimycin)
RN  - 42HK56048U (Tyrosine)
RN  - 935E97BOY8 (Folic Acid)
RN  - 94ZLA3W45F (Arginine)
RN  - EC 1.14.13.39 (Nitric Oxide Synthase)
RN  - EC 1.14.13.39 (Nitric Oxide Synthase Type III)
RN  - EC 1.14.13.39 (Nos3 protein, rat)
RN  - S8TIM42R2W (Bradykinin)
SB  - IM
MH  - Animals
MH  - Arginine/pharmacology
MH  - Bradykinin/pharmacology
MH  - Calcimycin/pharmacology
MH  - Cells, Cultured
MH  - Endothelium, Vascular/cytology/*metabolism
MH  - Folic Acid/pharmacology
MH  - Free Radical Scavengers/pharmacology
MH  - Homocysteine/antagonists & inhibitors/*pharmacology
MH  - Nitrates/metabolism
MH  - Nitric Oxide/*biosynthesis
MH  - Nitric Oxide Synthase/metabolism
MH  - Nitric Oxide Synthase Type III
MH  - Rats
MH  - Reactive Oxygen Species/metabolism
MH  - Recombinant Proteins/metabolism
MH  - Superoxides/metabolism
MH  - Tyrosine/*analogs & derivatives/metabolism
EDAT- 2000/09/21 11:00
MHDA- 2001/02/28 10:01
CRDT- 2000/09/21 11:00
PHST- 2000/09/21 11:00 [pubmed]
PHST- 2001/02/28 10:01 [medline]
PHST- 2000/09/21 11:00 [entrez]
AID - 10.1152/ajprenal.2000.279.4.F671 [doi]
PST - ppublish
SO  - Am J Physiol Renal Physiol. 2000 Oct;279(4):F671-8. doi: 
      10.1152/ajprenal.2000.279.4.F671.