He H, Herington A C, Roupas P
Centre for Hormone Research and Department of Clinical Biochemistry, Royal Children's Hospital, Parkville, Vic., Australia.
Reprod Fertil Dev. 1995;7(1):83-95. doi: 10.1071/rd9950083.
The effect of protein kinase C (PKC) modulation on gonadotrophin-induced ovarian granulosa cell differentiation was investigated by using an activator of PKC, phorbol 12-myristate 13-acetate (PMA) and inhibitors of PKC, sphingosine (SPH) and staurosporine (ST). The effects of PMA (at doses which activate PKC (10 ng mL-1), and down-regulate PKC (1000 ng mL-1)), sphingosine (25 microM) and staurosporine (10(-10)-10(-7) M) on gonadotrophin-induced granulosa cell differentiation were studied by the determination of steroidogenesis and cAMP accumulation in immature rat ovarian granulosa cells treated with or without pregnant mare serum gonadotrophin (100 mU mL-1). PMA (10 ng mL-1) inhibited gonadotrophin-induced granulosa cell steroidogenesis and cAMP accumulation. PMA (1000 ng mL-1)-induced down-regulation of PKC did not affect gonadotrophin-induced steroidogenesis. The inhibitory effect of PMA (10 ng mL-1) on gonadotrophin-induced granulosa cell steroidogenesis was not present in PKC-down-regulated cells. These data indicate that PKC activation by PMA inhibits gonadotrophin-induced steroidogenesis. SPH also inhibited gonadotrophin-induced steroidogenesis and cAMP accumulation. This effect of SPH was not affected by PMA-induced PKC down-regulation, indicating that this action of SPH does not require PKC or is mediated via a phorbol ester-insensitive PKC isoform. ST induced steroidogenesis in the absence of gonadotrophin, but was not synergistic with gonadotrophin. PMA-induced down-regulation of PKC abolished the effect of ST, suggesting that the action of ST requires PKC. The data suggest that ST and PMA, which antagonize each other in gonadotrophin-induced steroidogenesis, act via a PKC-mediated mechanism whereas the cAMP-associated actions of gonadotrophins and SPH are not dependent on PKC.
通过使用蛋白激酶C（PKC）激活剂佛波醇12 - 肉豆蔻酸酯13 - 乙酸酯（PMA）以及PKC抑制剂鞘氨醇（SPH）和星形孢菌素（ST），研究了PKC调节对促性腺激素诱导的卵巢颗粒细胞分化的影响。通过测定用或不用孕马血清促性腺激素（100 mU/mL）处理的未成熟大鼠卵巢颗粒细胞中的类固醇生成和cAMP积累，研究了PMA（激活PKC的剂量（10 ng/mL）和下调PKC的剂量（1000 ng/mL））、鞘氨醇（25 μM）和星形孢菌素（10⁻¹⁰ - 10⁻⁷ M）对促性腺激素诱导的颗粒细胞分化的影响。PMA（10 ng/mL）抑制促性腺激素诱导的颗粒细胞类固醇生成和cAMP积累。PMA（1000 ng/mL）诱导的PKC下调不影响促性腺激素诱导的类固醇生成。PKC下调的细胞中不存在PMA（10 ng/mL）对促性腺激素诱导的颗粒细胞类固醇生成的抑制作用。这些数据表明，PMA激活PKC抑制促性腺激素诱导的类固醇生成。SPH也抑制促性腺激素诱导的类固醇生成和cAMP积累。SPH的这种作用不受PMA诱导的PKC下调的影响，表明SPH的这种作用不需要PKC或通过佛波酯不敏感的PKC亚型介导。ST在没有促性腺激素的情况下诱导类固醇生成，但与促性腺激素无协同作用。PMA诱导的PKC下调消除了ST的作用，表明ST的作用需要PKC。数据表明，在促性腺激素诱导的类固醇生成中相互拮抗的ST和PMA通过PKC介导的机制起作用，而促性腺激素和SPH与cAMP相关的作用不依赖于PKC。
