title: Physiological roles of semenogelin I and zinc in sperm motility and semen coagulation on ejaculation in humans.
abstract: At ejaculation, human sperm are considered to be mechanically trapped and become immotile in the semen coagulum by binding to semenogelins (Sgs) from the seminal vesicle and zinc ions from the prostate. However, the physiological combined roles of the protein and heavy metal on sperm motility are unknown. Here, we have first demonstrated that Sg I alone, which does not form the semen coagulum without zinc, is an inhibitor of the motility of intact human sperm at physiological concentration. On the other hand, zinc ions alone had no effect on sperm motility, but confer recovery of sperm motility that has been inhibited by Sg I at a concentration equal to or less than 1 mg/ml. These observations suggest that the roles played by Sg I and zinc on sperm motility are not mechanical but physiological. Quartz crystal microbalance analysis suggests that the sperm extract first bind to Sg I and then zinc ions which subsequently increase the protein accumulation, suggesting that Sgs inhibit sperm motility by directly binding to the sperm surface. Further accumulation of Sg I mediated by zinc ions may entrap the quiescent sperm at semen ejaculation.
authors.affiliation: Biomedical Engineering Center, Toin University of Yokohama, 1614 Kurogane-cho, Aoba-ku, Yokohama 225-8502, Japan. yoshidak@cc.toin.ac.jp
authors.forename: Kaoru
authors.initials: K
authors.lastname: Yoshida
authors.forename: Natsuko
authors.initials: N
authors.lastname: Kawano
authors.forename: Miki
authors.initials: M
authors.lastname: Yoshiike
authors.forename: Manabu
authors.initials: M
authors.lastname: Yoshida
authors.forename: Teruaki
authors.initials: T
authors.lastname: Iwamoto
authors.forename: Masaaki
authors.initials: M
authors.lastname: Morisawa
mesh_terms: D000293:Adolescent; D000328:Adult; D004542:Ejaculation / Q000502:physiology*; D006801:Humans; D008297:Male; D012661:Semen / Q000166:cytology / Q000378:metabolism*; D029607:Seminal Vesicle Secretory Proteins / Q000302:isolation & purification / Q000494:pharmacology*; D013081:Sperm Motility / Q000187:drug effects*; D015032:Zinc / Q000494:pharmacology*
chemical_list: D029607:Seminal Vesicle Secretory Proteins; C424482:seminal vesicle-specific antigen; D015032:Zinc