title: Human spermatozoa capacitated with progesterone or a long incubation show accelerated internalization by an alkyl ether lysophospholipid.
abstract: OBJECTIVE
  To evaluate changes that occur in sperm plasma membranes during capacitation, the internalization of [(3)H]lyso-platelet activating factor ([(3)H]lyso-PAF) across the plasma membrane of human spermatozoa was measured as a function of incubation time or exposure to progesterone (P).
  
  
  METHODS
  In vitro cell culture study using human spermatozoa.
  
  
  METHODS
  Department of Obstetrics and Gynecology, School of Medicine, the University of Tokushima, Japan.
  
  
  METHODS
  Semen were obtained from three fertile healthy volunteers.
  
  
  METHODS
  The internalization of [(3)H]lyso-PAF across the plasma membranes of human spermatozoa that were incubated for an extended period or exposed to P was measured at 5, 20, 60, and 120 minutes after the addition of the phospholipid probe using the modified albumin back-exchange method.
  
  
  METHODS
  The percentage of capacitated and acrosome-reacted sperm and the proportion of internalization of lyso-PAF across the plasma membrane.
  
  
  RESULTS
  A 6-hour incubation period significantly increased the percentage of capacitated spermatozoa and the proportion of internalization of [(3)H]lyso-PAF across the plasma membrane of human spermatozoa compared with controls (capacitated spermatozoa, 20.3 +/- 10.6% vs. 8.5 +/- 1.8%; internalization 120 minutes after the addition of the phospholipid probe, 25.6 +/- 2.5% vs. 11.6 +/- 3.0%) (mean +/- SEM). Exposure to P significantly increased the percentage of capacitated spermatozoa compared with controls (19.6 +/- 6.8% vs. 11.0 +/- 2.4%) and also significantly accelerated the internalization of [(3)H]lyso-PAF compared with controls (internalization 120 minutes after the addition of the phospholipid probe, 26.2 +/- 1.8% vs. 21.4 +/- 1.1%).
  
  
  CONCLUSIONS
  The administration of P or a long incubation increased the proportion of internalization and consequently induced capacitation in human spermatozoa.
authors.affiliation: Department of Obstetrics and Gynecology, School of Medicine, University of Tokushima, Tokushima, Japan.
authors.forename: Shuji
authors.initials: S
authors.lastname: Yamano
authors.forename: Jun
authors.initials: J
authors.lastname: Yamazaki
authors.forename: Minoru
authors.initials: M
authors.lastname: Irahara
authors.forename: Akira
authors.initials: A
authors.lastname: Tokumura
authors.forename: Koji
authors.initials: K
authors.lastname: Nakagawa
authors.forename: Hidekazu
authors.initials: H
authors.lastname: Saito
mesh_terms: D002462:Cell Membrane / Q000378:metabolism; D002478:Cells, Cultured; D006801:Humans; D008297:Male; D010972:Platelet Activating Factor / Q000031:analogs & derivatives* / Q000493:pharmacokinetics*; D011374:Progesterone / Q000494:pharmacology*; D013075:Sperm Capacitation; D013094:Spermatozoa / Q000187:drug effects* / Q000502:physiology*; D013997:Time Factors
chemical_list: C029271:O-deacetyl platelet activating factor; D010972:Platelet Activating Factor; D011374:Progesterone