Kinetic Study of 17α-Estradiol Activity in Comparison with 17β-Estradiol and 17α-Ethynylestradiol

17α-estradiol (αE2), an endogenous stereoisomer of the hormone 17β-estradiol (E2), is capable binding to estrogen receptors (ER). We aimed mathematically describe, using experimental data, possible interactions between αE2 and sperm ER during process capacitation develop a kinetic model. The goal was compare suggested model with previously published results E2 17α-ethynylestradiol (EE2). HPLC-MS/MS method developed monitor changes concentration capacitation. calculated relative concentrations Bt were used for analysis. Rate constants k molar ratio n optimized construction theoretical B(t) curves. Modifications in αE2–ER discovered comparison models EE2. These new displayed autocatalytic formation unstable adduct cytoplasmic receptors. accumulates plasma membrane lipid bilayer increasing potential, when critical level reached, penetrates through inner layer into cytoplasm. It then rapidly reacts creates adduct. revealed dynamics action may contribute understanding tissue rejuvenation cancer-related physiology signaling.