Azarnia R, Chambers E L
J Exp Zool. 1976 Oct;198(1):65-77. doi: 10.1002/jez.1401980109.
The Ca and Mg content of unfertilized sea urchin eggs (3 and 21 mumole/ml eggs) remains remarkably constant over periods of hours, even when the eggs are suspended in Ca- or Mg-free sea water. After fertilization the Ca content of eggs in regular sea water increases sharply by about 20%, followed by a decrease to the unfertilized level by 40 minutes. However, if the fertilized eggs are washed three minutes in Ca-free sea water a sharp decrease in the Ca content occurs amounting to 30% of the total in the first 40 minutes, with little change thereafter. Suspension of the eggs in Ca-free sea water results in an even greater loss of Ca amounting to about 43% of the total in the same time interval, followed by a continuing slow loss. It is concluded that fertilization initiates the intracellular release of Ca, which is then extruded. For unwashed eggs this change is masked by the simultaneous generation of new extra-cellular coats with high affinity for Ca. Changes in the Mg content of fertilized eggs follow the same general pattern except that absorption of this divalent cation to the extracellular coats is minimal.
未受精的海胆卵的钙和镁含量（分别为3和21微摩尔/毫升卵）在数小时内保持相当稳定，即便卵悬浮于无钙或无镁的海水中。受精后，处于正常海水中的卵的钙含量急剧增加约20%，随后在40分钟内降至未受精时的水平。然而，如果受精后的卵在无钙海水中冲洗三分钟，钙含量会急剧下降，在前40分钟内下降幅度达总量的30%，之后变化不大。将卵悬浮于无钙海水中会导致钙流失更为严重，在相同时间间隔内约占总量的43%，随后持续缓慢流失。得出的结论是，受精引发了细胞内钙的释放，随后钙被排出。对于未冲洗的卵，这种变化被同时生成的对钙具有高亲和力的新细胞外被所掩盖。受精后卵中镁含量的变化遵循相同的总体模式，只是这种二价阳离子向细胞外被的吸收极少。
