Characterization of Intracellular Ca2+ Increase in Response to Progesterone and Cyclic Nucleotides in Mouse Spermatozoa1
Characterization of Intracellular Ca2+ Increase in Response to Progesterone and Cyclic Nucleotides in Mouse Spermatozoa1
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DOI：
10.1095/biolreprod63.1.113
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发表时间：
2000-07
期刊：
影响因子：
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通讯作者：
H. Kobori;S. Miyazaki;Y. Kuwabara
中科院分区：
文献类型：
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作者：
H. Kobori;S. Miyazaki;Y. Kuwabara
本文用小鼠精子头部Ca ~（2+）显像技术研究了顶体反应诱导剂孕酮和第二信使环核苷酸引起的精子胞内Ca ~（2+）浓度升高。孕酮以剂量依赖性方式（4-40 μM）诱导[Ca 2 +]i升高，主要在顶体后区。对于20 μM孕酮，42%的精子发生Ca 2+反应，分为两种类型：瞬时型（60%的反应细胞;持续时间，1-1.5分钟;平均幅度，335 nM）和延长型（40%; >3分钟; 730 nM）。延长的反应需要更高剂量的孕酮，和他们的发生增强显着预孵育2-4小时相比，短暂的反应。8-溴-cGMP（0.3-3 mM）比8-溴-cAMP更有效地诱导[Ca ~（2+）]i升高。对于1 mM 8-溴-cGMP，90%的细胞表现出短暂的Ca 2+反应（约1分钟; 220 nM），与预孵育时间无关。在无Ca ~（2+）的培养液中，大多数精子对孕酮和8-溴-cGMP无Ca ~（2+）反应。钙通道阻滞剂匹莫齐特完全阻断延长反应，部分抑制瞬时反应。这些结果表明，孕酮激活至少两个不同的Ca 2+内流途径，快速或缓慢的失活动力学，和一些精子显示两种类型的响应。环核苷酸介导的过程可能参与了孕酮诱导的[Ca ~（2+）]i升高。
Abstract Rises in intracellular Ca2+ concentration ([Ca2+]i) caused by progesterone, an inducer of the acrosome reaction, or by cyclic nucleotides, possible second messengers, were investigated by Ca2+ imaging of the head of individual mouse sperm. Progesterone induced a [Ca2+]i rise in a dose-dependent manner (4–40 μM), primarily in the postacrosomal region. For 20-μM progesterone, Ca2+ responses occurred in 42% of sperm, separated into two types: transient type (60% of responding cells; duration, 1–1.5 min; mean amplitude, 335 nM) and prolonged type (40%; >3 min; 730 nM). Prolonged responses required higher doses of progesterone, and their occurrence was enhanced significantly by preincubation for 2–4 h as compared with transient responses. 8-Bromo-cGMP (0.3–3 mM) induced a [Ca2+]i rise more effectively than did 8-bromo-cAMP. For 1-mM 8-bromo-cGMP, 90% of cells exhibited transient Ca2+ responses (∼1 min; 220 nM), independently of the preincubation time. In Ca2+-free medium, most sperm showed no Ca2+ response to progesterone and 8-bromo-cGMP. Pimozide, a Ca2+ channel blocker, completely blocked prolonged responses and partially inhibited transient responses. These results suggest that progesterone activates at least two distinct Ca2+ influx pathways, with fast or slow inactivation kinetics, and some sperm show both types of response. A cyclic nucleotide-mediated process could participate in the progesterone-induced [Ca2+]i rise.