Direct measurement of intracellular pH during metabolic derepression of the sea urchin egg
Direct measurement of intracellular pH during metabolic derepression of the sea urchin egg
复制标题
海胆卵代谢去抑制过程中直接测量细胞内 pH 值
作者：
S. Shen;R. Steinhardt
海胆卵在代谢受到抑制的状态下脱落，并在受精过程中得到抑制。这种抑制发生在两个阶段，其中第一个是由Ca2+的细胞内释放引起的（参考文献1,2）。据推测，第二阶段的抑制是通过增加细胞内pH3-5来完成的。此外，通过使用细胞匀浆测量细胞内pH值的尝试支持了细胞内pH值在卵子激活期间增加的观点5,6。我们在这里报告了海胆卵在受精和氨激活期间的细胞内pH值的直接测量。这些测量结果证明了受精或暴露于NH4Cl导致的细胞内pH值的假设增加，尽管pH值的变化与匀浆中报道的不同，并且似乎以比最初预期的更复杂的方式进行调节。
SEA URCHIN eggs are shed in a metabolically repressed state and are derepressed by fertilisation. This derepression occurs in two phases, the first of which is caused by an intracellular release of Ca2+ (refs 1,2). It has been postulated that the second phase of derepression is accomplished by an increase of intracellular pH3–5. Furthermore, attempts to measure intracellular pH by the use of cell homogenates have supported the idea that intracellular pH is increased during egg activation5,6. We report here direct measurements of intracellular pH of sea urchin eggs during fertilisation and activation by ammonia. These measurements demonstrate the postulated increase of intracellular pH resulting from fertilisation or exposure to NH4Cl, although the changes in pH differ from those reported in homogenates and seem to be regulated in a more complex manner than originally anticipated.