Biochemical and Physiological Studies on the Initiation Mechanism of Mammalian Spermatozoa

本研究的目的是探讨哺乳动物精子的胞内运动启动因子。由于腺苷3‘，5’-单磷酸(CAMP)是鲑鱼精子的细胞内运动启动因子，该未知核苷酸似乎是哺乳动物精子的细胞内运动启动因子。此外，金黄地鼠去膜精子只有在加入三磷酸腺苷和环磷酸腺苷的情况下才能活动。用放射免疫法测定，在金黄地鼠精子运动开始后，细胞内cAMP浓度立即升高。这种增加是由于精子运动启动时腺苷环化酶的激活所致。此外，电子显微镜观察证明，该酶仅分布在鞭毛部分，而不是在顶体区域，在运动起始过程中被激活。由于磷酸二酯酶rem…的活性在精子运动开始后的几分钟内，环状AMP更多地积聚在精子中。但在精子活动后，磷酸二酯酶活性升高，细胞内环磷酸腺苷水平逐渐降低。这些观察结果有力地表明，cAMP是金黄地鼠精子真正的细胞内运动起始因子。在公猪的精子上也得到了非常类似的结果。由于腺苷环化酶的活性受钙离子的调节，因此研究了钙离子对金黄地鼠精子启动的影响，因为该酶的激活剂可能是一种外部运动启动因子。当内部和外部的游离钙离子都被完全清除时，精子永远不会活动。但在外界加入该离子后，精子逐渐开始运动。这些结果表明，游离钙离子与精子的运动启动机制密切相关。较少

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