Bagger P V, Byskov A G, Christiansen M D, Bang L, Mortensen L
Department of Gynecology and Obstetrics, Rigshospitalet, University Hospital of Copenhagen, Denmark.
Acta Obstet Gynecol Scand. 1993 Oct;72(7):514-9. doi: 10.3109/00016349309058154.
Cumulus enclosed oocytes, cumulus enclosed oocytes denuded of their cumulus and cumulus free oocytes from 21 day old unstimulated mice were cultured for 18 hours in control medium supplemented with lithium chloride, dbcAMP and forskolin at various concentrations. In control medium 66% of the cumulus enclosed oocytes, 93% of the denuded oocytes, and 94% of the cumulus free oocytes resumed meiosis (germinal vesicle breakdown), whereas the levels of polar body formation were 27%, 12% and 39%, respectively. In the presence of lithium significantly more cumulus enclosed oocytes and cumulus free oocytes resumed meiosis and formed a polar body, whereas lithium had no effect on the denuded oocytes. Forskolin and dbcAMP stimulated resumption of meiosis and cumulus expansion in the cumulus enclosed oocytes and inhibited resumption of meiosis in the cumulus free oocytes. Lithium more or less eliminated this inhibitory effect of both forskolin and dbcAMP in the cumulus free oocytes. The results indicate (i) that activation of the cAMP second messenger path in the cumulus cells induces them to synthesize a meiosis inducing substance(s) which stimulates the oocyte to resume meiosis, and (ii) that other second messenger systems than the cAMP pathway, e.g. the phosphatidylinositol cycle, are involved in resumption of meiosis and polar body formation. We conclude that lithium enhances the capability of mouse oocytes for resumption of meiosis and polar body formation.
将来自21日龄未受刺激小鼠的卵丘包被卵母细胞、去除卵丘的卵丘包被卵母细胞和无卵丘卵母细胞，在添加了不同浓度氯化锂、二丁酰环磷腺苷（dbcAMP）和福斯高林的对照培养基中培养18小时。在对照培养基中，66%的卵丘包被卵母细胞、93%的去除卵丘的卵母细胞和94%的无卵丘卵母细胞恢复减数分裂（生发泡破裂），而极体形成水平分别为27%、12%和39%。在氯化锂存在的情况下，显著更多的卵丘包被卵母细胞和无卵丘卵母细胞恢复减数分裂并形成极体，而氯化锂对去除卵丘的卵母细胞没有影响。福斯高林和dbcAMP刺激卵丘包被卵母细胞恢复减数分裂和卵丘扩展，并抑制无卵丘卵母细胞恢复减数分裂。氯化锂或多或少消除了福斯高林和dbcAMP对无卵丘卵母细胞的这种抑制作用。结果表明：（i）卵丘细胞中cAMP第二信使途径的激活诱导它们合成一种减数分裂诱导物质，刺激卵母细胞恢复减数分裂；（ii）除cAMP途径外的其他第二信使系统，如磷脂酰肌醇循环，参与减数分裂恢复和极体形成。我们得出结论，氯化锂增强了小鼠卵母细胞恢复减数分裂和形成极体的能力。
