| Increased nitrite reductase activity of fetal versus adult ovine hemoglobin. | |
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MedLine Citation:
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PMID: 19028797 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Growing evidence indicates that nitrite, NO2-, serves as a circulating reservoir of nitric oxide (NO) bioactivity that is activated during physiological and pathological hypoxia. One of the intravascular mechanisms for nitrite conversion to NO is a chemical nitrite reductase activity of deoxyhemoglobin. The rate of NO production from this reaction is increased when hemoglobin is in the R conformation. Because the mammalian fetus exists in a low-oxygen environment compared with the adult and is exposed to episodes of severe ischemia during the normal birthing process, and because fetal hemoglobin assumes the R conformation more readily than adult hemoglobin, we hypothesized that nitrite reduction to NO may be enhanced in the fetal circulation. We found that the reaction was faster for fetal than maternal hemoglobin or blood and that the reactions were fastest at 50-80% oxygen saturation, consistent with an R-state catalysis that is predominant for fetal hemoglobin. Nitrite concentrations were similar in blood taken from chronically instrumented normoxic ewes and their fetuses but were elevated in response to chronic hypoxia. The findings suggest an augmented nitrite reductase activity of fetal hemoglobin and that the production of nitrite may participate in the regulation of vascular NO homeostasis in the fetus. |
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Authors:
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Arlin B Blood; Mauro Tiso; Shilpa T Verma; Jennifer Lo; Mahesh S Joshi; Ivan Azarov; Lawrence D Longo; Mark T Gladwin; Daniel B Kim-Shapiro; Gordon G Power |
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Publication Detail:
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Type: Comparative Study; Journal Article; Research Support, N.I.H., Extramural Date: 2008-11-21 |
Journal Detail:
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Title: American journal of physiology. Heart and circulatory physiology Volume: 296 ISSN: 0363-6135 ISO Abbreviation: Am. J. Physiol. Heart Circ. Physiol. Publication Date: 2009 Feb |
Date Detail:
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Created Date: 2009-01-27 Completed Date: 2009-03-12 Revised Date: 2010-09-23 |
Medline Journal Info:
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Nlm Unique ID: 100901228 Medline TA: Am J Physiol Heart Circ Physiol Country: United States |
Other Details:
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Languages: eng Pagination: H237-46 Citation Subset: IM |
Affiliation:
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Department of Pediatrics, Division of Neonatology, School of Medicine, Loma Linda University, Loma Linda, CA, USA. ablood@llu.edu |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Animals Anoxia / enzymology Biocatalysis Chronic Disease Disease Models, Animal Dithionite / chemistry Female Fetal Blood / enzymology* Fetal Hypoxia / enzymology Hemoglobins / chemistry, metabolism* Hydrogen-Ion Concentration Kinetics Methemoglobin / metabolism Nitric Oxide / blood* Nitrite Reductases / blood* Nitrites / blood* Oxygen / blood Pregnancy Protein Conformation Sheep |
| Grant Support | |
ID/Acronym/Agency:
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HD-03807/HD/NICHD NIH HHS; HL-058091/HL/NHLBI NIH HHS; HL-078706/HL/NHLBI NIH HHS |
| Chemical | |
Reg. No./Substance:
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0/Hemoglobins; 0/Nitrites; 10102-43-9/Nitric Oxide; 14844-07-6/Dithionite; 7782-44-7/Oxygen; 9008-37-1/Methemoglobin; EC 1.7.-/Nitrite Reductases |
| Comments/Corrections | |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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