17α-Estradiol (αE2) is a natural diastereoisomer of 17β-estradiol (E2). It is well known that αE2 can bind to estrogen receptors. However, its biological activity is less than that of E2 and is species and tissue specific. The goal of our study was to propose the mechanism of αE2 hormonal response in rat sperm during their capacitation in vitro and compare it with a previously studied mouse model. Concentration changes in externally added αE2 during capacitation of rat sperm were monitored by the high-performance liquid chromatographic method with tandem mass spectrometric detection (HPLC-MS/MS). The calculated values of relative concentrations Bt were subjected to kinetic analysis. The findings indicated that αE2 in rat sperm did not trigger autocatalytic reaction, in contrast to the mouse sperm, and that the initiation of the hormone penetration through the sperm plasma membrane was substantially faster in rats.

• Klíčová slova
• 17α-estradiol, HPLC MS/MS, capacitation, estrogen receptors, kinetics, rat, sperm,
• MeSH
• estradiol * chemie   MeSH
• kapacitace spermií * fyziologie   MeSH
• kinetika MeSH
• krysa rodu Rattus MeSH
• myši MeSH
• sperma metabolismus   MeSH
• tandemová hmotnostní spektrometrie MeSH
• zvířata MeSH
• Check Tag
• krysa rodu Rattus MeSH
• mužské pohlaví MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• estradiol * MeSH

17β-estradiol (estradiol) is a natural estrogen regulating reproduction including sperm and egg development, sperm maturation-called capacitation-and sperm⁻egg communication. High doses can increase germ cell apoptosis and decrease sperm count. Our aim was to answer the biological relevance of estradiol in sperm capacitation and its effect on motility and acrosome reaction to quantify its interaction with estrogen receptors and propose a model of estradiol action during capacitation using kinetic analysis. Estradiol increased protein tyrosine phosphorylation, elevated rate of spontaneous acrosome reaction, and altered motility parameters measured Hamilton-Thorne Computer Assisted Semen Analyzer (CASA) in capacitating sperm. To monitor time and concentration dependent binding dynamics of extracellular estradiol, high-performance liquid chromatography with tandem mass spectrometry was used to measure sperm response and data was subjected to kinetic analysis. The kinetic model of estradiol action during sperm maturation shows that estradiol adsorption onto a plasma membrane surface is controlled by Langmuir isotherm. After, when estradiol passes into the cytoplasm, it forms an unstable adduct with cytoplasmic receptors, which display a signalling autocatalytic pattern. This autocatalytic reaction suggests crosstalk between receptor and non-receptor pathways utilized by sperm prior to fertilization.

• Klíčová slova
• 17β-estradiol, CASA, HPLC MS/MS, acrosome reaction, autocatalysis, capacitation, kinetics, sperm,
• MeSH
• akrozomální reakce účinky léků   MeSH
• estradiol metabolismus   farmakologie   MeSH
• kapacitace spermií účinky léků   fyziologie   MeSH
• kinetika MeSH
• motilita spermií účinky léků   MeSH
• myši inbrední C57BL MeSH
• progesteron farmakologie   MeSH
• signální transdukce * MeSH
• sperma účinky léků   metabolismus   MeSH
• vysokoúčinná kapalinová chromatografie MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• estradiol MeSH
• progesteron MeSH