Roldan E R, Fleming A D
Department of Anatomy and Reproductive Biology, University of Hawaii School of Medicine, Honolulu 96822.
J Reprod Fertil. 1989 Jan;85(1):297-308. doi: 10.1530/jrf.0.0850297.
The Ca2+-ATPase antagonists quercetin and ethacrynic acid accelerated the onset of the acrosome reaction in guinea-pig spermatozoa incubated in the continuous presence of Ca2+, whereas furosemide had no effect, and sodium orthovanadate only affected sperm motility. When spermatozoa were preincubated in a 'Ca2+-free' medium, quercetin and ethacrynic acid shortened capacitation time: spermatozoa incubated for 1 h in 100-200 microM-ethacrynic acid showed 60-80% acrosome reactions when Ca2+ was added. Such spermatozoa were able to fertilize zona-free hamster eggs. Our results therefore point to the possible involvement of a Ca2+-ATPase in the regulation of intracellular Ca2+ in spermatozoa. Cysteine and dithiothreitol, both disulphide reducing agents, prevented the effects of quercetin and ethacrynic acid, suggesting that sulphydryl groups may be important for the expression of Ca2+-ATPase activity. Lysophosphatidylserine (LS) also prevented the stimulatory effect of ethacrynic acid, an effect similar to that shown by LS on lysophosphatidylcholine (LC). It is argued that both LS and LC could exert their action through an effect on the Ca2+-ATPase.
钙离子 - ATP酶拮抗剂槲皮素和依他尼酸可加速在持续存在钙离子的条件下孵育的豚鼠精子顶体反应的起始，而速尿无此作用，原钒酸钠仅影响精子活力。当精子在“无钙”培养基中预孵育时，槲皮素和依他尼酸可缩短获能时间：在100 - 200微摩尔依他尼酸中孵育1小时的精子，加入钙离子后显示出60 - 80%的顶体反应。此类精子能够使去透明带仓鼠卵受精。因此，我们的结果表明钙离子 - ATP酶可能参与精子细胞内钙离子的调节。半胱氨酸和二硫苏糖醇这两种二硫键还原剂可阻止槲皮素和依他尼酸的作用，这表明巯基对于钙离子 - ATP酶活性的表达可能很重要。溶血磷脂酰丝氨酸（LS）也可阻止依他尼酸的刺激作用，这种作用与LS对溶血磷脂酰胆碱（LC）的作用相似。有人认为LS和LC都可能通过对钙离子 - ATP酶的作用来发挥其功能。
