期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：1979
卷号：76
期号：11
页码：5699-5703
DOI：10.1073/pnas.76.11.5699
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：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.
