Canipari R, O'Connell M L, Meyer G, Strickland S
J Cell Biol. 1987 Aug;105(2):977-81. doi: 10.1083/jcb.105.2.977.
It is well established that rat ovarian granulosa cells produce tissue plasminogen activator (tPA). The synthesis and secretion of the enzyme are induced by gonadotropins, and correlate well with the time of follicular rupture in vivo. We have found that in contrast, mouse granulosa cells produce a different form of plasminogen activator, the urokinase-type (uPA). As with tPA synthesis in the rat, uPA production by mouse granulosa cells is induced by gonadotropins, dibutyryl cAMP, and prostaglandin E2. However, dexamethasone, a drug which has no effect on tPA synthesis in rat cells inhibits uPA synthesis in the mouse. Results of these determinations made in cell culture were corroborated by examining follicular fluid, which is secreted in vivo predominantly by granulosa cells, from stimulated rat and mouse ovarian follicles. Rat follicular fluid contained only tPA, and mouse follicular fluid only uPA, indicating that in vivo, granulosa cells from the two species are secreting different enzymes. The difference in the type of plasminogen activator produced by the rat and mouse granulosa cells was confirmed at the messenger RNA level. After hormone stimulation, only tPA mRNA was present in rat cells, whereas only uPA mRNA was found in mouse cells. Furthermore, the regulation of uPA levels in mouse cells occurs via transient modulation of steady-state levels of mRNA, a pattern similar to that seen with tPA in rat cells.
众所周知，大鼠卵巢颗粒细胞可产生组织型纤溶酶原激活物（tPA）。该酶的合成和分泌由促性腺激素诱导，且与体内卵泡破裂时间密切相关。我们发现，与之相反，小鼠颗粒细胞产生的是纤溶酶原激活物的另一种形式，即尿激酶型（uPA）。与大鼠tPA的合成情况一样，小鼠颗粒细胞产生uPA也受促性腺激素、二丁酰环磷腺苷（dibutyryl cAMP）和前列腺素E2诱导。然而，地塞米松这种对大鼠细胞tPA合成无影响的药物却能抑制小鼠细胞uPA的合成。通过检测卵泡液（体内主要由颗粒细胞分泌），对细胞培养中的这些测定结果进行了验证，这些卵泡液来自受刺激的大鼠和小鼠卵巢卵泡。大鼠卵泡液只含tPA，而小鼠卵泡液只含uPA，这表明在体内，这两个物种的颗粒细胞分泌不同的酶。大鼠和小鼠颗粒细胞产生的纤溶酶原激活物类型差异在信使核糖核酸（mRNA）水平得到了证实。激素刺激后，大鼠细胞中只存在tPA mRNA，而小鼠细胞中只发现uPA mRNA。此外，小鼠细胞中uPA水平的调节是通过mRNA稳态水平的短暂调节实现的，这一模式与大鼠细胞中tPA的情况相似。
