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| Content Provider | PubMed Central |
|---|---|
| Author | Hyne, Ross V. Garbers, David L. |
| Abstract | Experiments were designed to determine the interrelationship between cyclic AMP and Ca2+ during the processes of sperm capacitation and the acrosome reaction. In minimal culture media containing pyruvate and lactate as substrates, guinea pig spermatozoa required a minimum of 1.0-1.5 hr to capacitate in the presence of 1.7 mM Ca2+ and a minimum of 0.5-1.0 hr to capacitate in the absence of added Ca2+. Sperm cyclic AMP concentrations were increased by as much as 30-fold within 0.5 min after addition of cells to various media containing Ca2+, and the concentrations then remained increased for up to 4 hr. When the cells were added to several Ca2+-deficient media, however, cyclic AMP concentrations increased only about 3-fold within 0.5 min and then returned to basal concentrations within 2 min. D-600, a calcium transport antagonist, completely blocked the Ca2+-induced increase in sperm cyclic AMP concentrations. In contrast to capacitation, the acrosome reaction failed to occur in the absence of extracellular Ca2+. After capacitation of spermatozoa in a Ca2+-free medium, addition of Ca2+ caused an increase in sperm cyclic AMP concentrations within 1 min and a maximal number of spermatozoa showing an acrosome reaction within 10 min. The addition of 1-methyl-3-isobutylxanthine along with Ca2+ had a synergistic effect on the increase in cyclic AMP. Neither 1-methyl-3-isobutylxanthine nor 8-Br cyclic AMP induced an acrosome reaction in capacitated spermatozoa in the absence of Ca2+, but both significantly decreased the time required for maximal expression of the acrosome reaction in the presence of Ca2+. These results suggest that the sperm acrosome reaction is associated with both a primary transport of Ca2+ and a Ca2+-dependent increase in sperm cyclic AMP concentrations. Because a cyclic AMP analogue did not induce an acrosome reaction in the absence of added Ca2+, the increase in sperm cyclic AMP concentrations induced by Ca2+ probably reflects one of a number of Ca2+-dependent events associated with the acrosome reaction. |
| Starting Page | 5699 |
| File Format | |
| ISSN | 10916490 |
| e-ISSN | 10916490 |
| Journal | Proceedings of the National Academy of Sciences of the United States of America |
| Issue Number | 11 |
| Volume Number | 76 |
| Language | English |
| Publisher Date | 1979-11-01 |
| Access Restriction | Open |
| Subject Keyword | Research in Higher Education |
| Content Type | Text |
| Resource Type | Article |
| Subject | Multidisciplinary |
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