Control of superoxide and nitric oxide formation during human sperm capacitation.
We studied the modulation of superoxide anion (O(2).(-)) and nitric oxide (NO.) generation during human sperm capacitation (changes needed for the acquisition of fertility). The production of NO. (diaminofluorescein-2 fluorescence assay), but not that of O(2).(-) (luminescence assay), related to sperm capacitation was blocked by inhibitors of protein kinase C, Akt, protein tyrosine kinase, etc., but not by those of protein kinase A. Extracellular calcium (Ca(2+)) controlled O(2).(-) synthesis but extra- and intracellular Ca(2+) regulated NO. formation. Zinc inhibited capacitation and formation of O(2).(-) and NO.. Zinc chelators (TPEN and EDTA) and sulfhydryl-targeted compounds (diamide and N-ethylmaleimide) stimulated capacitation and formation of O(2).(-) and NO.; superoxide dismutase (SOD) and nitric oxide synthase inhibitor (L-NMMA) prevented these events. Diphenyliodonium (flavoenzyme inhibitor) blocked capacitation and related O(2).(-) synthesis but promoted NO. formation, an effect canceled by SOD and L-NMMA. NADPH induced capacitation and NO. (but not O(2).(-)) synthesis and these events were blocked by L-NMMA and not by SOD. Integration of these data on O(2).(-) and NO. production during capacitation reinforces the concept that a complex, but flexible, network of factors is involved and probably is associated with rescue mechanisms, so that spermatozoa can achieve successful fertilization.
de Lamirande
Eve
E
McGill University Hospital Centre at Royal Victoria Hospital, McGill University, Montréal, QC, Canada. edelamirande@yahoo.com
Lamothe
Geneviève
G
Villemure
Michèle
M
D001713:Biphenyl Compounds / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism; D002614:Chelating Agents / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006801:Humans; D008297:Male; D009249:NADP / Q000037:antagonists & inhibitors; D009569:Nitric Oxide / Q000378:metabolism*; D009861:Onium Compounds / Q000494:pharmacology; D011494:Protein Kinases / Q000378:metabolism; D017382:Reactive Oxygen Species; D012102:Reproductive Control Agents; D013075:Sperm Capacitation; D013094:Spermatozoa / Q000166:cytology / Q000201:enzymology*; D013438:Sulfhydryl Compounds / Q000378:metabolism; D013482:Superoxide Dismutase / Q000037:antagonists & inhibitors*; D013481:Superoxides / Q000378:metabolism*; D015032:Zinc / Q000378:metabolism; D019323:omega-N-Methylarginine / Q000494:pharmacology
D001713:Biphenyl Compounds; D002614:Chelating Agents; D004791:Enzyme Inhibitors; D009861:Onium Compounds; D017382:Reactive Oxygen Species; D012102:Reproductive Control Agents; D013438:Sulfhydryl Compounds; C031291:diphenyliodonium; D013481:Superoxides; D019323:omega-N-Methylarginine; D009569:Nitric Oxide; D009249:NADP; D013482:Superoxide Dismutase; D011494:Protein Kinases; D015032:Zinc; D002118:Calcium