Einspanier A, Jurdzinski A, Hodges J K
Department of Reproductive Biology, German Primate Center, Göttingen.
Biol Reprod. 1997 Jul;57(1):16-26. doi: 10.1095/biolreprod57.1.16.
Luteinization is a complex differentiation process involving the interaction of extrinsic and intraovarian factors. The aim of this study was to examine the components of an intraovarian oxytocin (OT) system during the periovulatory period in the marmoset monkey, as well as the possible relationship of these components to other factors involved in the luteinization process, using immunohistochemistry and cell culture techniques. Ovaries were collected on Day 7 of the follicular phase (before the endogenous LH surge) and on Day 8 (22 h after an exogenous hCG application, but before ovulation). Before the endogenous LH increase, OT immunoreactivity was detectable at low levels in most antral follicles, where its presence was confined to antral granulosa cell (GC) layers. In contrast, immunoreactivity for the OT receptor (OTR) was localized primarily in the basal GC layer. After application of exogenous hCG, there was a marked enhancement in both the staining intensity and the number of cells positive for OT and the OTR in all GC layers of antral follicles, especially in the preovulatory follicle. Progesterone receptor and 3beta-hydroxysteroid dehydrogenase activity in GC were clearly present only when follicles were obtained after gonadotropin stimulation. Secretion of authentic OT was demonstrated from cultured GC obtained before the LH surge, with highest amounts in cells cultured from preovulatory as opposed to smaller antral follicles. OT production could be stimulated by the application of hCG to the GC cultured from preovulatory follicles, whereas the gonadotropin was without effect on GC from small follicles. FSH had no effect on OT production by GC from either follicle type. Application of OT to the cultures caused an increase in progesterone production by GC from large preovulatory follicles but was without effect on steroidogenesis by cells from small antral follicles. These results describing the presence and distribution of OT and OTR and their modulation by hCG, as well as the luteotrophic effect of OT in cultured GC from preovulatory follicles, implicate OT as a paracrine mediator in the luteinization process in the primate ovary.
黄体化是一个复杂的分化过程，涉及外在因素和卵巢内因素的相互作用。本研究的目的是利用免疫组织化学和细胞培养技术，研究狨猴排卵期前后卵巢内催产素（OT）系统的组成部分，以及这些组成部分与黄体化过程中其他相关因素的可能关系。在卵泡期第7天（内源性促黄体生成素激增前）和第8天（外源性人绒毛膜促性腺激素应用后22小时，但排卵前）采集卵巢。在内源性促黄体生成素增加之前，大多数窦状卵泡中可检测到低水平的OT免疫反应性，其存在仅限于窦状颗粒细胞（GC）层。相比之下，OT受体（OTR）的免疫反应性主要定位于基底GC层。应用外源性人绒毛膜促性腺激素后，窦状卵泡所有GC层中OT和OTR阳性细胞的染色强度和数量均显著增强，尤其是在排卵前卵泡中。只有在促性腺激素刺激后获得卵泡时，GC中的孕酮受体和3β-羟基类固醇脱氢酶活性才明显存在。在促黄体生成素激增前获得的培养GC中证实有真实OT的分泌，排卵前卵泡培养的细胞中分泌量最高，而较小的窦状卵泡培养的细胞中分泌量较低。将人绒毛膜促性腺激素应用于排卵前卵泡培养的GC可刺激OT的产生，而该促性腺激素对小卵泡的GC无影响。促卵泡激素对两种卵泡类型的GC产生OT均无影响。将OT应用于培养物中可使排卵前大卵泡的GC孕酮生成增加，但对小窦状卵泡细胞的类固醇生成无影响。这些结果描述了OT和OTR的存在、分布及其受hCG的调节，以及OT对排卵前卵泡培养GC的黄体营养作用，表明OT是灵长类卵巢黄体化过程中的旁分泌介质。
