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Studies related to progesterone‐induced hamster sperm acrosome reaction
Author(s) -
Llanos Miguel N.,
Anabalón Mireya C.
Publication year - 1996
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/(sici)1098-2795(199611)45:3<313::aid-mrd8>3.0.co;2-v
Subject(s) - acrosome reaction , ionomycin , ionophore , hamster , sperm , nigericin , biology , exocytosis , egta , benzamidine , endocrinology , medicine , biochemistry , calcium , enzyme , membrane , secretion , stimulation , botany
Experiments were designed to characterize the effect of progesterone on the hamster sperm acrosome reaction (AR). Progesterone stimulated exocytosis of previously capacitated spermatozoa in a dose‐dependent manner Progesterone‐3‐(O‐carboxymethyl)oxime:BSA conjugate also induced AR when added to capacitated sperm suspensions. EGTA and La 3+ , added 10 min before progesterone, completely abolished the steroid‐stimulatory effect. Benzamidine, a trypsin inhibitor, also inhibited AR when added to sperm cells 10 min before progesterone. This effect was avoided when spermatozoa were treated with the Ca2+ ionophore ionomycin. Conversely, the H+ ionophore PCCP, or the Na + /K + ionophore nigericin, did not prevent the effect of the inhibitor. Results suggest that progesterone acts on the hamster sperm plasma membrane to stimulate exocytosis, which requires external Ca2+ and presumably Ca2+ influx. In addition, a sperm trypsin like protease may be part of the mechanism by which progesterone stimulates AR. Since the ionomycin‐induced AR does not require this proteolytic activity, the possible involvement of such an enzyme in the progesterone‐stimulated Ca2+ influx necessary for the occurrence of AR is discussed. © 1996 Wiley‐Liss, Inc.