Document Detail


Ascorbic acid in human seminal plasma is protected from iron-mediated oxidation, but is potentially exposed to copper-induced damage.
MedLine Citation:
PMID:  9308796     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The aim of this study was to assess the interaction of endogenous ascorbate with iron and copper ions in aerobic seminal plasma. The rate of ascorbate consumption was measured by high-performance liquid chromatography and by the concentration of its primary oxidation product, ascorbyl radical (Asc.-) detected by electron spin resonance spectroscopy. The modification in the levels of Asc.- was used to investigate non-invasively and in real time whether metal ions, either present in this fluid or exogenously added, were catalytically active. The Asc.- was detected in seminal plasma as well as in whole semen of all subjects and was unaffected by superoxide dismutase, catalase or metal chelators. These findings and the rapid decrease of Asc.- under nitrogen suggest that Asc.- is probably a result of non-metal-catalysed air auto-oxidation, a reaction generating low levels of reactive oxygen species. Loading of seminal plasma with either Fe2+ or Fe3+ up to a concentration of 50 microM did not increase, or increased only slightly, the rate of ascorbate oxidation. Taking into consideration the concentrations of iron-binding proteins in this fluid, these results suggest that seminal plasma possesses a 'physiological ligand(s)' able to maintain iron ions in a catalytically inactive form. Our results indicate that citrate, which is present in seminal plasma at very high concentrations (10-25 mM), is responsible for the inhibition of iron-dependent catalysis. On the contrary, the loss of ascorbate and the levels of Asc.- were significantly increased by the addition of physiologically relevant concentrations (1 microM) of copper ions (Cu2+ but especially Cu+). We suggest that seminal plasma is potentially exposed to copper-mediated oxidation, a finding that could be of importance in situations of increased copper-loading such as in some pathological conditions or in smoking subjects.
Authors:
A Menditto; D Pietraforte; M Minetti
Related Documents :
19237316 - A life-threatening paediatric case of acute autoimmune haemolytic anaemia (aiha) succes...
17197376 - No virological failure in semen during properly suppressive antiretroviral therapy desp...
11277876 - Inhibition of neutrophil chemotaxis by pig seminal plasma in vitro: a potential method ...
2222076 - Antisticking protein factors in buffalo blood serum.
2293556 - Relationship between dihydropyrimidine dehydrogenase activity and plasma 5-fluorouracil...
2440666 - A case of klinefelter's syndrome associated with hypothalamic-pituitary dysfunction cau...
Publication Detail:
Type:  Clinical Trial; Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Human reproduction (Oxford, England)     Volume:  12     ISSN:  0268-1161     ISO Abbreviation:  Hum. Reprod.     Publication Date:  1997 Aug 
Date Detail:
Created Date:  1997-11-20     Completed Date:  1997-11-20     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  8701199     Medline TA:  Hum Reprod     Country:  ENGLAND    
Other Details:
Languages:  eng     Pagination:  1699-705     Citation Subset:  IM    
Affiliation:
Department of Clinical Biochemistry, Istituto Superiore di Sanità, Roma, Italy.
Export Citation:
APA/MLA Format     Download EndNote     Download BibTex
MeSH Terms
Descriptor/Qualifier:
Ascorbic Acid / metabolism*
Catalysis
Copper / metabolism*
Electron Spin Resonance Spectroscopy
Humans
Iron / metabolism*
Male
Oxidation-Reduction
Reference Values
Semen / metabolism*
Chemical
Reg. No./Substance:
50-81-7/Ascorbic Acid; 7439-89-6/Iron; 7440-50-8/Copper

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


Previous Document:  Disintegration of chromosomes in dead sperm cells as revealed by injection into mouse oocytes.
Next Document:  Conservative management of azoospermia following steroid abuse.