Kinetics of the progesterone-induced acrosome reaction and its relation to intracellular calcium responses in individual human spermatozoa

Claire V. Harper, Christopher L. R. Barratt, Stephen J. Publicover, Jackson C. Kirkman-Brown

Research output: Contribution to journalArticle

20 Citations (Scopus)

Abstract

Progesterone at 3 microM triggers a biphasic (transient and sustained) increase in intracellular calcium ([Ca(2+)](i)) in human sperm, which is believed to be a prerequisite for progesterone-induced acrosome reaction (AR). As very little is known about how AR occurrence, latency, and completion relate to the characteristics of the progesterone-induced [Ca(2+)](i) signal, we examined these events using fluorescence microscopy of individual living human sperm. Direct assessment of acrosomal status after calcium imaging showed no differences in kinetics or amplitude of the preceding progesterone-induced calcium responses in acrosome-reacted and acrosome-intact cells, which indicates that the amplitude of the [Ca(2+)](i) signal is not the critical determinant of AR. Chelation of extracellular calcium to arrest AR at varying times after progesterone stimulation revealed that maximal AR occurred immediately following progesterone stimulation, during the initial transient calcium influx rather than during the sustained calcium response. Attempts to follow acrosomal dispersal in real-time by staining with the acidic organelle probes LysoTracker DND-99 and dapoxyl (2-aminoethyl) sulphonamide (DAES) proved inconclusive due to heterogeneous labeling of the cell population. Surprisingly, the dye was often not confined to the acrosome but stained the whole sperm head, which suggests that only a subpopulation of human sperm cells contains a sufficiently acidic acrosome.

Original languageEnglish
Pages (from-to)933-939
Number of pages7
JournalBiology of Reproduction
Volume75
Issue number6
DOIs
Publication statusPublished - Dec 2006

Fingerprint

Acrosome Reaction
Progesterone
Spermatozoa
Acrosome
Calcium
Sperm Head
Sulfonamides
Fluorescence Microscopy
Organelles
Coloring Agents
Staining and Labeling
Population

Keywords

  • Acids/metabolism
  • Acrosome Reaction/drug effects
  • Amines
  • Calcium/metabolism
  • Carbocyanines
  • Cell Membrane/metabolism
  • Fluorescent Dyes
  • Humans
  • Hydrogen-Ion Concentration
  • Ionophores/pharmacology
  • Kinetics
  • Male
  • Progesterone/pharmacology
  • Pyridinium Compounds
  • Quaternary Ammonium Compounds
  • Signal Transduction/drug effects
  • Spermatozoa/drug effects

Cite this

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title = "Kinetics of the progesterone-induced acrosome reaction and its relation to intracellular calcium responses in individual human spermatozoa",
abstract = "Progesterone at 3 microM triggers a biphasic (transient and sustained) increase in intracellular calcium ([Ca(2+)](i)) in human sperm, which is believed to be a prerequisite for progesterone-induced acrosome reaction (AR). As very little is known about how AR occurrence, latency, and completion relate to the characteristics of the progesterone-induced [Ca(2+)](i) signal, we examined these events using fluorescence microscopy of individual living human sperm. Direct assessment of acrosomal status after calcium imaging showed no differences in kinetics or amplitude of the preceding progesterone-induced calcium responses in acrosome-reacted and acrosome-intact cells, which indicates that the amplitude of the [Ca(2+)](i) signal is not the critical determinant of AR. Chelation of extracellular calcium to arrest AR at varying times after progesterone stimulation revealed that maximal AR occurred immediately following progesterone stimulation, during the initial transient calcium influx rather than during the sustained calcium response. Attempts to follow acrosomal dispersal in real-time by staining with the acidic organelle probes LysoTracker DND-99 and dapoxyl (2-aminoethyl) sulphonamide (DAES) proved inconclusive due to heterogeneous labeling of the cell population. Surprisingly, the dye was often not confined to the acrosome but stained the whole sperm head, which suggests that only a subpopulation of human sperm cells contains a sufficiently acidic acrosome.",
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Kinetics of the progesterone-induced acrosome reaction and its relation to intracellular calcium responses in individual human spermatozoa. / Harper, Claire V.; Barratt, Christopher L. R.; Publicover, Stephen J.; Kirkman-Brown, Jackson C.

In: Biology of Reproduction, Vol. 75, No. 6, 12.2006, p. 933-939.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Kinetics of the progesterone-induced acrosome reaction and its relation to intracellular calcium responses in individual human spermatozoa

AU - Harper, Claire V.

AU - Barratt, Christopher L. R.

AU - Publicover, Stephen J.

AU - Kirkman-Brown, Jackson C.

PY - 2006/12

Y1 - 2006/12

N2 - Progesterone at 3 microM triggers a biphasic (transient and sustained) increase in intracellular calcium ([Ca(2+)](i)) in human sperm, which is believed to be a prerequisite for progesterone-induced acrosome reaction (AR). As very little is known about how AR occurrence, latency, and completion relate to the characteristics of the progesterone-induced [Ca(2+)](i) signal, we examined these events using fluorescence microscopy of individual living human sperm. Direct assessment of acrosomal status after calcium imaging showed no differences in kinetics or amplitude of the preceding progesterone-induced calcium responses in acrosome-reacted and acrosome-intact cells, which indicates that the amplitude of the [Ca(2+)](i) signal is not the critical determinant of AR. Chelation of extracellular calcium to arrest AR at varying times after progesterone stimulation revealed that maximal AR occurred immediately following progesterone stimulation, during the initial transient calcium influx rather than during the sustained calcium response. Attempts to follow acrosomal dispersal in real-time by staining with the acidic organelle probes LysoTracker DND-99 and dapoxyl (2-aminoethyl) sulphonamide (DAES) proved inconclusive due to heterogeneous labeling of the cell population. Surprisingly, the dye was often not confined to the acrosome but stained the whole sperm head, which suggests that only a subpopulation of human sperm cells contains a sufficiently acidic acrosome.

AB - Progesterone at 3 microM triggers a biphasic (transient and sustained) increase in intracellular calcium ([Ca(2+)](i)) in human sperm, which is believed to be a prerequisite for progesterone-induced acrosome reaction (AR). As very little is known about how AR occurrence, latency, and completion relate to the characteristics of the progesterone-induced [Ca(2+)](i) signal, we examined these events using fluorescence microscopy of individual living human sperm. Direct assessment of acrosomal status after calcium imaging showed no differences in kinetics or amplitude of the preceding progesterone-induced calcium responses in acrosome-reacted and acrosome-intact cells, which indicates that the amplitude of the [Ca(2+)](i) signal is not the critical determinant of AR. Chelation of extracellular calcium to arrest AR at varying times after progesterone stimulation revealed that maximal AR occurred immediately following progesterone stimulation, during the initial transient calcium influx rather than during the sustained calcium response. Attempts to follow acrosomal dispersal in real-time by staining with the acidic organelle probes LysoTracker DND-99 and dapoxyl (2-aminoethyl) sulphonamide (DAES) proved inconclusive due to heterogeneous labeling of the cell population. Surprisingly, the dye was often not confined to the acrosome but stained the whole sperm head, which suggests that only a subpopulation of human sperm cells contains a sufficiently acidic acrosome.

KW - Acids/metabolism

KW - Acrosome Reaction/drug effects

KW - Amines

KW - Calcium/metabolism

KW - Carbocyanines

KW - Cell Membrane/metabolism

KW - Fluorescent Dyes

KW - Humans

KW - Hydrogen-Ion Concentration

KW - Ionophores/pharmacology

KW - Kinetics

KW - Male

KW - Progesterone/pharmacology

KW - Pyridinium Compounds

KW - Quaternary Ammonium Compounds

KW - Signal Transduction/drug effects

KW - Spermatozoa/drug effects

U2 - 10.1095/biolreprod.106.054627

DO - 10.1095/biolreprod.106.054627

M3 - Article

C2 - 16957023

VL - 75

SP - 933

EP - 939

JO - Biology of Reproduction

JF - Biology of Reproduction

SN - 0006-3363

IS - 6

ER -