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Differential sensitivity of progesterone‐ and zona pellucida‐induced acrosome reactions to pertussis toxin
Author(s) -
Tesarik Jan,
Carreras Alfonso,
Mendoza Carmen
Publication year - 1993
Publication title -
molecular reproduction and development
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.745
H-Index - 105
eISSN - 1098-2795
pISSN - 1040-452X
DOI - 10.1002/mrd.1080340210
Subject(s) - acrosome reaction , pertussis toxin , zona pellucida , acrosome , biology , sperm , oocyte , andrology , microbiology and biotechnology , g protein , signal transduction , embryo , medicine , genetics
Pertussis toxin‐sensitive guanine nucleotide‐binding regulatory proteins (G proteins) have previously been shown to mediate the zona pellucida‐induced acrosome reaction in mammalian sperm. In this study we compared the inhibitory effect of pertussis toxin on the zona‐induced acrosome reaction in human spermatozoa with that on the reaction induced by progesterone, another physiological acrosome reaction‐promoting stimulus associated with the ovulated oocyte. Up to the concentration of 1 μg/ml, pertussis toxin did not produce any direct effects on the acrosome reaction frequency nor did it influence sperm movement and viability. However, preincubation of spermatozoa with the toxin at a concentration of 100 ng/ml completely abolished the increase in the acrosome reaction frequency upon subsequent exposure to solubilized zona pellucida material. In contrast, the same treatment did not impair the ability of spermatozoa to initiate the acrosome reaction in response to progesterone. Moreover, the preincubation with pertussis toxin did not modify the changes in the intracellular concentration of calcium ions occurring after progesterone addition. These data suggest that different physiological stimuli may utilize different signal transduction pathways to induce the human sperm acrosome reaction. © 1993 Wiley‐Liss, Inc.