Frayne J, Townsend D, Nicholson H D
Department of Anatomy, University of Bristol, UK.
J Reprod Fertil. 1996 Jul;107(2):299-306. doi: 10.1530/jrf.0.1070299.
Oxytocin is present in the mammalian testis where it increases contractility of seminiferous tubules in vitro and has been implicated in sperm transport. The present study investigated whether oxytocin affects the transport of spermatozoa from the testis in vivo. In rats, mature spermatozoa are first seen in the testis 42 days postpartum and arrive in the epididymis at about day 45. Male Wistar rats were given daily subcutaneous injections of either oxytocin (0.5 micrograms), the oxytocin antagonist des Gly-NH2d(CH2)5-[D-Tyr2,Thr4]OVT (0.2 micrograms) or saline from day 40 postpartum. Groups of six animals were killed 2 h after their last injection on days 43, 44, 45 and 46 postpartum. Testes were removed and fixed in Bouin's fluid for histological examination and the number of spermatozoa in the epididymides was counted. Spermatozoa were seen in the epididymis earlier in the oxytocin-treated rats (day 43) than in the control animals (day 44), and treatment with the antagonist delayed the appearance of spermatozoa in the epididymis until day 45. When the testes were examined, residual bodies, which were used as an indicator of spermiation, were seen only in one control animal before day 44. Residual bodies were seen in the testes of all oxytocin-treated rats on day 43 but were not detected until day 45 in the oxytocin antagonist-treated rats. These data show that in rats oxytocin can affect the arrival of spermatozoa in the epididymis. Although this may be due in part to effects on tubal transport or the secretion of tubular fluid, these findings suggest that the peptide may affect spermiation.
催产素存在于哺乳动物的睾丸中，它在体外可增强生精小管的收缩性，并与精子运输有关。本研究调查了催产素在体内是否影响睾丸中精子的运输。在大鼠中，产后42天首次在睾丸中看到成熟精子，约在第45天到达附睾。从产后第40天起，给雄性Wistar大鼠每日皮下注射催产素（0.5微克）、催产素拮抗剂去甘氨酰胺基（CH2）5-[D-酪氨酸2，苏氨酸4]催产素（0.2微克）或生理盐水。在产后第43、44、45和46天，每组6只动物在最后一次注射后2小时处死。取出睾丸并固定在布安氏液中进行组织学检查，并计算附睾中的精子数量。在接受催产素治疗的大鼠（第43天）中，附睾中出现精子的时间比对照动物（第44天）更早，而用拮抗剂治疗会使附睾中精子的出现延迟到第45天。检查睾丸时，仅在第44天之前的一只对照动物中看到用作精子释放指标的残余小体。在第43天，所有接受催产素治疗的大鼠睾丸中都可见残余小体，但在接受催产素拮抗剂治疗的大鼠中直到第45天才检测到。这些数据表明，在大鼠中催产素可影响精子到达附睾。虽然这可能部分归因于对输卵管运输或管腔液分泌的影响，但这些发现表明该肽可能影响精子释放。
