The neurohypophyseal hormone oxytocin (OT) plays critical roles in lactation and parturition, whilst its function in male reproduction system is largely unknown. This study aims to investigate the effect of OT on regulating transepithelial ion transport in rat cauda epididymal epithelium. Using RT-PCR, western blot and immunohistochemical analysis, we found that OT receptor (OTR) was expressed and localized at the basal membrane of rat cauda epididymal epithelium. The short-circuit current (I_SC) measurement showed that basolateral application of OT to the primary cultured rat cauda epididymal epithelial cells elicited an increase in I_SC, which was abrogated by pretreating the epithelial cells with CFTR_inh-172, a blocker of cystic fibrosis transmembrane conductance regulator (CFTR). Pretreatment with the prostaglandin H synthase (PGHS) inhibitors indomethacin and piroxicam, or the non-selective antagonists of PGE₂ receptor EP2 or EP4, AH-6809 and AH-23848, significantly attenuated OT-stimulated I_SC response. Furthermore, the generation of prostaglandin E₂ (PGE₂) was measured using enzyme-linked immunosorbent assay, demonstrating that OT induced a substantial increase in PGE₂ release from primary cultured rat cauda epididymal epithelial cells. In conclusion, activation of OTR by OT triggered PGE₂ release, resulting in CFTR-dependent Cl⁻ secretion through paracrine/autocrine pathways in rat cauda epididymal epithelium.

中文翻译：

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催产素刺激的大鼠马尾附睾上皮中Cl-分泌的细胞机制。

神经下垂体激素催产素（OT）在泌乳和分娩中起着关键作用，而其在男性生殖系统中的功能尚不清楚。本研究旨在探讨OT对大鼠马尾附睾上皮中跨上皮离子运输的调节作用。使用RT-PCR，免疫印迹和免疫组化分析，我们发现OT受体（OTR）被表达并定位于大鼠马尾附睾上皮的基底膜。短路电流（I _SC）测量表明，将OT基底外侧应用到原代培养的大鼠马尾附睾上皮细胞中会引起I _SC的增加，这可以通过用CFTR _inh预处理上皮细胞来消除-172，囊性纤维化跨膜电导调节剂（CFTR）的阻滞剂。用前列腺素H合酶（PGHS）抑制剂吲哚美辛和吡罗昔康或PGE ₂受体EP2或EP4的非选择性拮抗剂，AH-6809和AH-23848进行预处理，可以显着减弱OT刺激的I _SC反应。此外，使用酶联免疫吸附测定法测量了前列腺素E ₂（PGE ₂）的产生，表明OT诱导了从原代培养的大鼠马尾附睾上皮细胞中PGE ₂释放的显着增加。总之，通过OT OTR的活化而触发PGE ₂释放，导致CFTR依赖性氯^- 在大鼠马尾附睾上皮中通过旁分泌/自分泌途径分泌。