title: Intracellular calcium measurements in individual human sperm demonstrate that the majority can respond to progesterone.
abstract: OBJECTIVE
  To determine if human spermatozoa could be immobilized and intracellular calcium measurements made on individual cells to measure what proportion can respond to P.
  
  
  METHODS
  Spermatozoa were loaded with Fura 2 (Sigma Chemical Co., Poole, Dorest, United Kingdom) and suspended in 10% gelatin at 37 degrees C. A thin layer of the suspension was cooled to room temperature (20 degrees C to 25 degrees C) and [Ca2+]i was measured with a fluorescence microscope equipped with dual wavelength excitation and an image analysis system.
  
  
  METHODS
  University-based laboratory.
  
  
  METHODS
  Semen was obtained from four fertile donors to a donor insemination program.
  
  
  METHODS
  None.
  
  
  METHODS
  [Ca2+]i was calculated from the ratio of Fura 2 fluorescence excited at 340 nm and that excited at 366 nm.
  
  
  RESULTS
  One hundred six of 114 sperm examined (93%) demonstrated a significant response to P but the size and duration of the response was variable.
  
  
  CONCLUSIONS
  These data demonstrate that most sperm can respond to P.
authors.affiliation: University Department of Obstetrics and Gynaecology, St Michael's Hospital, Bristol, United Kingdom.
authors.forename: A
authors.initials: A
authors.lastname: Plant
authors.forename: E A
authors.initials: EA
authors.lastname: McLaughlin
authors.forename: W C
authors.initials: WC
authors.lastname: Ford
mesh_terms: D002118:Calcium / Q000378:metabolism*; D005456:Fluorescent Dyes; D016257:Fura-2; D006801:Humans; D008297:Male; D011374:Progesterone / Q000494:pharmacology*; D013081:Sperm Motility; D013094:Spermatozoa / Q000187:drug effects* / Q000378:metabolism*
chemical_list: D005456:Fluorescent Dyes; D011374:Progesterone; D002118:Calcium; D016257:Fura-2