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This Article Full Text Full Text (PDF) All Versions of this Article: 69/1/347    most recent biolreprod.102.012716v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Ecroyd, H. W. Articles by Aitken, R. J. Search for Related Content PubMed PubMed Citation Articles by Ecroyd, H. W. Articles by Aitken, R. J. Agricola Articles by Ecroyd, H. W. Articles by Aitken, R. J.

Endogenous Redox Activity in Mouse Spermatozoa and Its Role in Regulating the Tyrosine Phosphorylation Events Associated with Sperm Capacitation¹

Reproductive Science Group,³ and ARC Centre of Excellence in Biotechnology and Development,⁴ School of Environmental and Life Sciences, University of Newcastle, Callaghan, NSW 2308, Australia

We investigated the role of endogenous redox activity in regulating the signal transduction pathway leading to tyrosine phosphorylation in mouse spermatozoa. Endogenous redox activity was monitored using a luminol-peroxidase chemiluminescent probe. Chemiluminescence increased in spermatozoa that were actively undergoing cAMP-mediated tyrosine phosphorylation events associated with capacitation and was inhibited in a dose-dependent manner by addition of catalase or diphenylene iodonium, both of which also inhibited tyrosine phosphorylation within the cell at points downstream of cAMP. Excluding bicarbonate from the incubation medium reduced the redox activity of sperm by 80–90% and dramatically reduced tyrosine phosphorylation. This study provides the first evidence that tyrosine phosphorylation associated with capacitation in mouse spermatozoa is redox regulated by a flavinoid-containing enzyme involving mediation by hydrogen peroxide. Bicarbonate regulated the redox activity of mouse spermatozoa, and this regulation may contribute to the impact of this anion on tyrosine phosphorylation during capacitation of mouse spermatozoa.

¹ This study was funded by an Australian Research Council project grant (A099180338).

² Correspondence. Fax: 61-1-(2) 4921 6927; jaitken{at}mail.newcastle.edu.au

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