CHARACTERIZATION OF CA-2+ UPTAKE BY GUINEA-PIG EPIDIDYMAL SPERMATOZOA
CHARACTERIZATION OF CA-2+ UPTAKE BY GUINEA-PIG EPIDIDYMAL SPERMATOZOA
复制标题
DOI：
10.1095/biolreprod37.5.1097
复制
发表时间：
1987-12-01
影响因子：
3.6
通讯作者：
LARDY, HA
中科院分区：
文献类型：
--
作者：
CORONEL, CE;LARDY, HA
对豚鼠精子的钙摄取进行了比较研究，分别与新鲜附睾精子和预先培养在化学定义的无钙获能介质中的细胞进行了比较。新鲜精子的钙摄取几乎可以忽略不计，但在37℃孵育20min后，钙摄取显著增加。在丙酮酸和乳酸盐存在的情况下。在没有这些底物的情况下孵育的精子仅积累了完全培养条件下细胞摄取45Ca~(2+)的34%。单糖葡萄糖、果糖和甘露糖以及非代谢糖2-脱氧葡萄糖和蔗糖抑制钙离子通透性的增强。在蔗糖浓度为6 mM时，外加氯化钠浓度在0 mM~145 mM范围内不影响细胞对钙的吸收。获能精子的呼吸活性不仅高于未获能精子，而且受到钙离子的刺激。Ca~(2+)对新鲜精子呼吸作用无明显影响。钙摄取量的增加与介质的pH升高有关。可能存在一种通过豚鼠精子质膜钙通透性的调节机制，并控制与受精过程相关的生理事件的发生。体外实验表明，糖的组成、能量底物乳酸和丙酮酸的有效性以及生殖道液的pH值对体内细胞内钙离子的可获得性起着重要作用。在预培养过程中，钙通透性的增强可能是验证是否发生获能的一个有用的指标。
Comparative studies of Ca2+-uptake by guinea pig spermatozoa were performed with fresh epididymal sperm and with cells preincubated in a chemically defined, Ca2+-free medium for capacitation. Calcium uptake was negligible in fresh spermatozoa, but increased dramatically after the 20 min of incubation at 37.degree. C in the presence of pyruvate and lactate. Spermatozoa incubated in the absence of these substrates accumulated only 34% as much 45Ca2+ as was taken up by cells in complete medium. The monosaccharides glucose, fructose, and mannose and the nonmetabolizable sugars 2-deoxyglucose and sucrose inhibited the enhancement of Ca2+-permeability. In the presence of 6 mM sucrose 45Ca2+ uptake was not influenced by external sodium chloride concentration between 0 mM and 145 mM. The respiratory activity of the capacitated spermatozoa not only was higher than that of uncapacitated cells, but it was stimulated by Ca2+. No effect of Ca2+ on respiration of fresh spermatozoa was detected. An increase in calcium uptake was associated with increasing pH of the medium. It is possible that a regulatory mechanism through the calcium permeability of the plasma membrane of guinea pig spermatozoa exists and controls the development of physiological events related with the fertilization process. The sugar composition, the availability of the energy substrates lactate and pyruvate, and the pH of the reproductive tract fluids could play an important role in the accessibility of Ca2+ into the cells in vivo, as has been demonstrated in vitro. The enhancement of calcium permeability during the preincubation could be a useful indicator to verify if capacitation has occurred.