诱导完全成熟和中等大小的非洲爪蟾卵母细胞成熟（减数分裂）的离子需求。
Ionic requirements for induction of maturation (meiosis) in full-grown and medium-sized Xenopus laevis oocytes.
作者信息
Baltus E, Hanocq-Quertier J, Pays A, Brachet J
出版信息
Proc Natl Acad Sci U S A. 1977 Aug;74(8):3461-5. doi: 10.1073/pnas.74.8.3461.
There is already good evidence that calcium ions are involved in the induction of maturation in full-grown amphibian oocytes; we show here that other cations (K+, Mg2+) also play a role in this process. Full-grown (1.3 mm in diameter) and medium-sized (0.8-1.0 mm in diameter) oocytes were compared in the present study. It was found that, provided the medium is K+-free, valinomycin induces maturation in full-grown, but not in medium-sized, oocytes. Increasing the CaCl2 (20 mM) or the MgSO4 (40 mM) content of the medium induces maturation in full-grown, but not in medium-sized, oocytes; however, the latter undergo germinal vesicle breakdown after treatment with either progesterone or ionophore A23187 if there is an excess of Ca2+ or Mg2+ in the medium. Maturation is possible in a Na+-free medium, but amiloride inhibits germinal vesicle breakdown when NaCl is present in the medium. It is concluded that maturation is controlled by changes in the balance between the various ions rather than by Ca2+ alone.
已有充分证据表明钙离子参与了完全成熟的两栖类卵母细胞的成熟诱导过程；我们在此表明其他阳离子（K⁺、Mg²⁺）在这一过程中也发挥作用。在本研究中，对完全成熟的（直径1.3毫米）和中等大小的（直径0.8 - 1.0毫米）卵母细胞进行了比较。结果发现，如果培养基不含K⁺，缬氨霉素可诱导完全成熟的卵母细胞成熟，但不能诱导中等大小的卵母细胞成熟。增加培养基中CaCl₂（20 mM）或MgSO₄（40 mM）的含量可诱导完全成熟的卵母细胞成熟，但不能诱导中等大小的卵母细胞成熟；然而，如果培养基中Ca²⁺或Mg²⁺过量，后者在用孕酮或离子载体A23187处理后会发生生发泡破裂。在无Na⁺的培养基中可以发生成熟，但当培养基中存在NaCl时，氨氯吡脒会抑制生发泡破裂。得出的结论是，成熟是由各种离子之间平衡的变化控制的，而不是仅由Ca²⁺控制。
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