FREE CALCIUM CHANGES ASSOCIATED WITH HORMONE ACTION IN AMPHIBIAN OOCYTES
FREE CALCIUM CHANGES ASSOCIATED WITH HORMONE ACTION IN AMPHIBIAN OOCYTES
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DOI：
10.1016/0012-1606(80)90329-2
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发表时间：
1980-01-01
影响因子：
2.7
通讯作者：
GUERRIER, P
中科院分区：
文献类型：
--
作者：
MOREAU, M;VILAIN, JP;GUERRIER, P
Ca 2+敏感电极和发光蛋白obelin和水母发光蛋白与卵母细胞的无尾类非洲爪蟾和urodeles Ambystoma mexicanum和Pleurodeles waltlii检测任何变化的内部游离Ca 2+，这可能会导致孕酮或激动剂刺激。记录到一个显著的Ca 2+激增：从0.7 × 10 - 4到0.5 × 10 - 4。10-6 M在未刺激的卵母细胞中为7 × 10 - 6。10-6 M刺激后但在生殖囊泡破裂（GVBD）之前。还测量了Ca 2+外排，但其占内部Ca 2+瞬态的不到0.2%;这种外排在没有外部Ca的情况下不发生。正常情况下，即使当二价阳离子不存在于外部介质中时，响应于孕酮、对羟基亚甲基磺酸盐（PHMPS）或Mn 2+的Ca 2+激增和成熟也会发生。与此相反，外部二价阳离子是必要的诱导减数分裂和Ca 2+瞬态的K+离子载体缬氨霉素。HCO 3-也触发减数分裂并导致Ca 2+释放，但释放以完全不同的动力学发生。不完全生长或季节性休眠的卵母细胞以及10 mM茶碱或普鲁卡因处理的卵母细胞既不释放Ca 2+也不响应激素。细胞内释放的Ca ~（2+）可能是两栖类卵母细胞在激素刺激后的主要第二信使，如海星。
Ca2+-sensitive electrodes and the photoproteins obelin and aequorin were used with the oocytes of the anuran Xenopus laevis and the urodeles Ambystoma mexicanum and Pleurodeles waltlii to detect any changes in internal free Ca2+ which might result from progesterone or agonist stimulation. A dramatic Ca2+ surge was recorded: from 0.7 .times. 10-6 M in the unstimulated oocyte to 7 .times. 10-6 M after stimulation but before germinal vesicle breakdown (GVBD). Ca2+ efflux was also measured, but it accounted for less than 0.2% of the internal Ca2+ transient; this efflux did not take place in the absence of external Ca. The Ca2+ surge and maturation in response to progesterone, p-hydroxymethylenesulfonate (PHMPS), or Mn2+ occurred normally even when divalent cations were absent from the external medium. In contrast, external divalent cations were necessary for the induction of meiosis and a Ca2+ transient by the K+ ionophore valinomycin. HCO3- also triggers meiosis and causes Ca2+ release, but the release occurs with quite different kinetics. Incompletely grown or seasonally dormant oocytes as well as 10 mM theophylline- or procaine-treated oocytes neither release Ca2+ nor response to the hormone. Intracellular released Ca2+ is likely to be the major 2nd messenger following hormone stimulation in amphibian oocytes as in starfish.