Florman H M, First N L
Department of Meat and Animal Science, University of Wisconsin, Madison 53706.
Dev Biol. 1988 Aug;128(2):453-63. doi: 10.1016/0012-1606(88)90307-7.
The regulation of acrosomal exocytosis in capacitated bovine spermatozoa by soluble extracts of zonae pellucidae was examined. Kinetic studies demonstrated that zonae pellucidae stimulated synchronous acrosome reactions. The t1/2 of this process was 5-10 min and response was maximal at 20 min. The apparent initial rate of exocytosis in sperm populations was dependent upon the concentration of zona pellucida protein, with an ED50 and a maximally effective dosage of 20 and 50 ng protein/microliter, respectively. Zonae pellucidae caused up to a 48-fold increase in the apparent initial rate and a 3- to 4-fold stimulation in the net occurrence of exocytosis. In contrast, solubilized zonae pellucidae did not induce acrosome reactions in uncapacitated sperm. The development of a capacitated state, as assayed by the ability of sperm to fertilize eggs in vitro, was compared to the expression of zona pellucida-regulated acrosome reactions in a series of kinetic experiments. Both activities were manifest with similar kinetics and displayed identical dependencies toward stimulatory and inhibitory agents in vitro. It is concluded that capacitation is an essential prerequisite for the induction of acrosomal exocytosis in bovine sperm by the zona pellucida.
研究了透明带可溶性提取物对获能牛精子顶体胞吐作用的调节。动力学研究表明，透明带可刺激同步顶体反应。该过程的半衰期为5 - 10分钟，反应在20分钟时达到最大值。精子群体中胞吐作用的表观初始速率取决于透明带蛋白的浓度，其半数有效剂量（ED50）和最大有效剂量分别为20和50 ng蛋白/微升。透明带可使表观初始速率增加多达48倍，并使胞吐作用的净发生率提高3至4倍。相比之下，溶解的透明带不会诱导未获能精子发生顶体反应。在一系列动力学实验中，将通过精子体外受精能力测定的获能状态的发展与透明带调节的顶体反应的表达进行了比较。这两种活性都具有相似的动力学表现，并且在体外对刺激剂和抑制剂表现出相同的依赖性。得出的结论是，获能是透明带诱导牛精子顶体胞吐作用的必要前提条件。
