title: Sequence of ejaculation affects the spermatozoon as a carrier and its message.
abstract: It is a widespread misunderstanding that the human ejaculation produces a homogeneous fluid with constant environment for the spermatozoa. On the contrary, spermatozoa are mainly expelled together with the zinc-rich prostatic fluid in the first ejaculation fractions. In nature, these spermatozoa most likely enter the cervical mucus before any significant contact with the later, sperm hostile fractions takes place. Spermatozoa collected in the laboratory for diagnosis, treatment or research purposes face challenges in the form of light, high oxygen concentration, low carbon dioxide concentration, increased pH, extreme variations in osmolarity, and changed bioavailability of zinc and calcium in the man-made laboratory product called seminal plasma. Possible future implications of these unphysiological conditions are discussed in relation to assisted reproduction and sperm research.
authors.affiliation: Assisted Conception Unit, Birmingham Women's Hospital and Reproductive Biology and Genetics Group, University of Birmingham, Metchley Park Road, Birmingham B15 2TG, UK. L.Bjorndahl@bham.ac.uk
authors.forename: Lars
authors.initials: L
authors.lastname: Björndahl
authors.forename: Ulrik
authors.initials: U
authors.lastname: Kvist
mesh_terms: D002118:Calcium / Q000378:metabolism; D002245:Carbon Dioxide / Q000378:metabolism; D002582:Cervix Mucus / Q000378:metabolism; D002843:Chromatin / Q000378:metabolism; D004542:Ejaculation; D005260:Female; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008027:Light; D008297:Male; D018384:Oxidative Stress; D010100:Oxygen / Q000378:metabolism; D012099:Reproductive Techniques; D012661:Semen / Q000378:metabolism; D013073:Sperm Agglutination; D013081:Sperm Motility; D013094:Spermatozoa / Q000378:metabolism / Q000473:pathology*; D013997:Time Factors; D015032:Zinc / Q000378:metabolism
chemical_list: D002843:Chromatin; D002245:Carbon Dioxide; D015032:Zinc; D010100:Oxygen; D002118:Calcium