Llanos M N, Ronco A M
Unit of Reproductive Biology, INTA, University of Chile, Santiago.
Cell Biochem Funct. 1994 Dec;12(4):289-96. doi: 10.1002/cbf.290120410.
The present report describes experiments to evaluate phospholipid methyltransferase activity in golden hamster spermatozoa incubated under different conditions. Washed cauda epididymal sperm were incubated with taurine, in the presence or absence of epinephrine. At various times, the sperm were separated, and phospholipid methyltransferase activity measured. Also, at each time, aliquots of the sperm suspension were assayed for motility, and acrosome reactions. Some sperm incubated in the presence of taurine and epinephrine were capacitated by 3.5 h, because about 40 per cent of them can undergo the acrosome reaction 10 min after addition of the fusogen lysophosphatidylcholine. In epinephrine-free incubations the fusogen failed to stimulate acrosome reactions. On the other hand, epinephrine stimulated by twofold phospholipid methyltransferase activity from '0 time' incubated sperm, in comparison to that observed in taurine-treated cells. Enzyme activities from both taurine or epinephrine plus taurine-treated cells decreased as the incubation time of the sperm suspension increased. Kinetic properties of the sperm phospholipid methyltransferase activity were modified by the presence of taurine and epinephrine when S-adenosylmethionine was used as the substrate. These results suggest that refined molecular events occur in the sperm cell during the acquisition of fertilizing ability.
本报告描述了评估在不同条件下孵育的金黄仓鼠精子中磷脂甲基转移酶活性的实验。将附睾尾精子洗涤后，在有或无肾上腺素存在的情况下与牛磺酸一起孵育。在不同时间，分离精子并测量磷脂甲基转移酶活性。此外，在每个时间点，对精子悬液的等分试样进行活力和顶体反应测定。一些在牛磺酸和肾上腺素存在下孵育的精子在3.5小时后获能，因为在添加融合剂溶血磷脂酰胆碱后10分钟，其中约40%的精子可发生顶体反应。在无肾上腺素的孵育中，融合剂未能刺激顶体反应。另一方面，与在牛磺酸处理的细胞中观察到的相比，肾上腺素使从“0时间”开始孵育的精子的磷脂甲基转移酶活性提高了两倍。随着精子悬液孵育时间的增加，牛磺酸或肾上腺素加牛磺酸处理的细胞的酶活性均降低。当以S-腺苷甲硫氨酸作为底物时，牛磺酸和肾上腺素的存在改变了精子磷脂甲基转移酶活性的动力学特性。这些结果表明，在精子获得受精能力的过程中，精子细胞内发生了精细的分子事件。
