Open AccessZona pellucida-induced acrosome reaction in human sperm: dependency on activation of pertussis toxin-sensitive Gi protein and extracellular calcium, and priming effect of progesterone and follicular fluid
Author(s) -
Alessandro Schuffner,
Hadley S. Bastiaan,
Eyup Hakan Duran,
Zin-Yong Lin,
Mahmood Morshedi,
D Franken,
Sergio Oehninger
Publication year - 2002
Publication title -
molecular human reproduction
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.143
H-Index - 122
eISSN - 1460-2407
pISSN - 1360-9947
DOI - 10.1093/molehr/8.8.722
Subject(s) - acrosome reaction , follicular fluid , zona pellucida , pertussis toxin , acrosome , sperm , biology , extracellular , medicine , endocrinology , andrology , oocyte , microbiology and biotechnology , receptor , biochemistry , g protein , embryo , botany
In these studies, we aimed to characterize the effects of the physiological, homologous agonists of the acrosome reaction, i.e. the zona pellucida (ZP) and progesterone/follicular fluid, on human sperm. The specific aims of our studies were: (i) to examine the dependency of the solubilized ZP-induced acrosome reaction on G(i) protein activation and presence of extracellular calcium; and (ii) to determine whether progesterone/follicular fluid exert a priming or synergist effect on the solubilized ZP-induced acrosome reaction. Highly motile sperm from fertile donors were exposed to the agonists in a microassay and the acrosomal status of live sperm was determined by indirect immunofluorescence using PSA-FITC/Hoechst double-staining. Pretreatment with pertussis-toxin (100 ng/ml) and EGTA (2.5 mmol/l) significantly inhibited the ZP-induced acrosome reaction without affecting the spontaneous rate of exocytosis. Progesterone (1.25 microg/ml) and human follicular fluid (10%) exerted a priming, time-dependent effect on the ZP-induced acrosome reaction. These studies demonstrated that: (i) acrosomal exocytosis of capacitated human sperm triggered by the homologous ZP is dependent on the activation of G(i) proteins (pertussis toxin-sensitive) and the presence of extracellular calcium; and (ii) progesterone and follicular fluid exert a priming effect on the ZP-induced acrosome reaction.