Filippi S, Vannelli G B, Granchi S, Luconi M, Crescioli C, Mancina R, Natali A, Brocchi S, Vignozzi L, Bencini E, Noci I, Ledda F, Forti G, Maggi Mario
Andrology Unit, Department of Clinical Physiopathology, University of Florence, viale Pieraccini 6, 50139 Florence, Italy.
Mol Cell Endocrinol. 2002 Jul 31;193(1-2):89-100. doi: 10.1016/s0303-7207(02)00101-6.
Oxytocin (OT) is a neurohypophysial hormone with unclear physiological functions in the male. Several previous studies indicated that OT might have a role in the ejaculatory process, stimulating sperm release from the epididymal storage. In this study we investigated on the presence and function of OT receptor (OTR) in rabbit and human epididymis. By using RT-PCR, Western and binding studies, we found that OTR gene and protein is expressed in the human epididymis and stimulates in vitro contractility. The immunolocalization of OTR suggests that the receptor is not only present in the smooth muscle cells of the human epididymis but also in the epithelial compartment. Experiments performed in rabbit epididymal epithelial (rEE) cells in culture indicate that OT induces the release of an other potent stimulator of epididymal contractility, endothelin-1 (ET-1), Blocking the ET(A) subtype of the ET-1 receptors, by using a specific antagonist (BQ-123), partially counteracts the contractile effect of OT, suggesting positive interactions between the two peptides in regulating epididymal contractility. Finally, to investigate whether an acute OT administration increases sperm release also in humans, we treated oligozoospermic patients with an intravenous bolus of OT (2.5 IU), just before sperm collection. In a small, single blind study, we found that OT almost doubled sperm retrieval when compared with vehicle administration. Our results indicate that OT might have physiological functions also in the male, controlling epididymal motility and sperm progression through the male genital tract.
催产素（OT）是一种神经垂体激素，其在男性体内的生理功能尚不清楚。此前的多项研究表明，OT可能在射精过程中发挥作用，刺激精子从附睾储存部位释放。在本研究中，我们调查了OT受体（OTR）在兔和人类附睾中的存在情况及功能。通过逆转录聚合酶链反应（RT-PCR）、蛋白质免疫印迹和结合研究，我们发现OTR基因和蛋白在人类附睾中表达，并能刺激体外收缩性。OTR的免疫定位表明，该受体不仅存在于人类附睾的平滑肌细胞中，也存在于上皮区室。在培养的兔附睾上皮（rEE）细胞中进行的实验表明，OT可诱导另一种附睾收缩性的强效刺激物内皮素-1（ET-1）的释放。使用特异性拮抗剂（BQ-123）阻断ET-1受体的ET(A)亚型，可部分抵消OT的收缩作用，提示这两种肽在调节附睾收缩性方面存在正向相互作用。最后，为了研究急性给予OT是否也能增加人类精子的释放，我们在采集精子前，对少精子症患者静脉推注OT（2.5国际单位）。在一项小型单盲研究中，我们发现与给予赋形剂相比，OT使精子回收量几乎增加了一倍。我们的结果表明，OT在男性体内可能也具有生理功能，通过控制附睾的运动性和精子在男性生殖道中的推进来发挥作用。
