Biochemical and Physiological Studies on the Initiation Mechanism of Mammalian Spermatozoa

本研究的目的是研究哺乳动物精子胞内运动起始因子。由于腺苷3',5'-单磷酸腺苷（环AMP）已被确定为鲑鱼鱼类精子细胞内运动的起始因子，该肽似乎也是哺乳动物精子细胞内运动的起始因子。此外，脱膜的仓鼠精子只有在ATP和环AMP同时加入时才能运动。用重免疫法测定，在仓鼠精子开始运动后，细胞内环AMP浓度立即升高。这种增加被认为是由于精子运动开始时腺苷酸环化酶的激活。电镜观察证实，该酶仅分布于鞭毛部分，不在顶体区域，在运动起始过程中被激活。由于磷酸二酯酶活性在精子运动开始后的几分钟内处于较低水平，因此环amp能够在精子中积累。各精子开始运动后，磷酸二酯酶活性逐渐升高，胞内环amp水平逐渐降低。这些观察结果有力地表明环AMP是仓鼠精子胞内运动的真正起始因子。在公猪精子上得到了非常相似的结果。由于腺苷酸环化酶的活性受钙离子的调控，因此研究了钙离子对仓鼠精子启动的影响，因为该酶的激活剂被认为是一种外部运动启动因子。当内部和外部的游离钙离子被完全去除时，精子永远不会运动。但在外部加入这种离子后，精子逐渐开始运动。这些结果表明，游离钙离子与精子运动起始机制密切相关。少

The aim of the present reaearch project is to investigate the intracellular motility initiation factor for mammalian spermatozoa. Since adenosine 3',5'-monophosphate (cyclic AMP) has been identified as the intracellullar motility initiation factor for salmonid fish spermatozoa, this uncleotide is seemed to be the intracellular motility initiation factor for mammalian spermatozoa. Moreover, demembraneted spermatozoa of hamster became motile only when ATP and cyclic AMP were added together. The intracellular concentration of cyclic AMP, which was determined by redioimmunoassay, increased immediately after the motility initiated in hamster spermatozoa. This increase was provided to be due to an activation of adenylate cyclase upon the initiation of the sperm motility. Furthermore, electron microscopical observation proved that this enzyme distributed at only flagella part, not at acrosomal region, was activated during the motility initiation process.Since activity of phosphodiesterase rem … More ained low for a few minutes after the initiation of sperm motility, cyclic amp was able to accumulate in the spermatozoa. However, the phosphodiesterase activity increased after every spermatozoa became to move, the intracellular cyclic amp level gradually decreased. These observation strongly suggest that cyclic AMP is the real intracellular motility initiation factor for the spermatozoa of hamster. Quite similar results were obtained on the spermatozoa of boar. As adenylate cyclase activity is regulated by calcium ion, effect of this ion on the initiation of the spermatozoa of hamster was examined, because the activator of this enzyme is expected to be an external motility initiation factor. When both internal and external free calcium ion was completely removed, the spermatozoa never became motile. But addition of this ion externally, the spermatozoa gradually initiated to move. These results indicate that free calcium ion must closely correlated with the motility initiation mechanism of the spermatozoa. Less