Fusion of prostasomes to human spermatozoa stimulates the acrosome reaction.
OBJECTIVE
To determine the effect of the fusion of prostasomes to spermatozoa on the acrosome reaction.


METHODS
In vitro study of human spermatozoa.


METHODS
Healthy volunteers in an academic research environment.


METHODS
Healthy volunteer men, 25 to 35 years old.


METHODS
Human semen was fractionated into spermatozoa and prostasomes. Fusion of prostasome to spermatozoa was performed at pH 5.5. Progesterone (1 microM) was added when required.


METHODS
Evaluation of the acrosome reaction by fluorescence microscopy.


RESULTS
The percentage of spontaneously acrosome-reacted cells was very low unless the Ca(2+)-ionophore A 23187 was added. The treatment of spermatozoa with 1 microM of progesterone scarcely affected the acrosome reaction; a pretreatment in conditions permitting fusion increased it. The addition of progesterone to prostasome-fused spermatozoa further increased the extent of the acrosome reaction.


CONCLUSIONS
The H(+)-dependent fusion with prostasomes makes spermatozoa more sensitive to the effect of progesterone on acrosome-reaction induction.
Palmerini
Carlo A
CA
Department of Biochemical Sciences and Molecular Biotechnology, University of Perugia, Perugia, Italy.
Saccardi
Carla
C
Carlini
Enrico
E
Fabiani
Roberto
R
Arienti
Giuseppe
G
D020101:Acrosome Reaction / Q000502:physiology*; D000001:Calcimycin / Q000494:pharmacology; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007476:Ionophores / Q000494:pharmacology; D008297:Male; D008561:Membrane Fusion; D011374:Progesterone / Q000494:pharmacology; D011467:Prostate / Q000378:metabolism*; D013094:Spermatozoa / Q000187:drug effects / Q000502:physiology*
D007476:Ionophores; D000001:Calcimycin; D011374:Progesterone