Goldsmith A R, Nicholls T J
J Endocrinol. 1984 Sep;102(3):353-6. doi: 10.1677/joe.0.1020353.
Male starlings which had fully developed testes under 11-h daily photoperiods were subjected for 10 weeks to daylengths either increasing or decreasing by 30 min per week. In both cases testicular regression occurred; in the former case this was complete due to photorefractoriness, and was accompanied by a postnuptial moult and a marked (P less than 0.01) rise in plasma prolactin concentration. In the latter case the rate of gonadal regression was slow and variable and no moulting was observed. Plasma prolactin remained very low. Eventually the birds which had experienced decreasing photoperiods were transferred to long (16 h) days; they were shown to be photosensitive since their testes redeveloped rapidly. There was also a rise in plasma prolactin, the birds eventually showed the full testicular regression characteristic of photorefractoriness, and moulting occurred. These results show that raised prolactin secretion is not associated with short-day-induced testicular regression but only with long-day-induced photorefractoriness.
在每日11小时光照周期下睾丸已完全发育的雄性椋鸟，被置于每周光照时长增加或减少30分钟的环境中10周。在这两种情况下，睾丸均发生退化；在前一种情况下，由于光不应性，退化完全，同时伴随着婚后换羽以及血浆催乳素浓度显著升高（P<0.01）。在后一种情况下，性腺退化速度缓慢且多变，未观察到换羽现象。血浆催乳素水平一直很低。最终，经历光照时长减少的鸟类被转移到长光照（16小时）环境中；结果显示它们具有光敏感性，因为其睾丸迅速重新发育。血浆催乳素也有所升高，这些鸟类最终表现出光不应性所特有的完全睾丸退化，并且发生了换羽。这些结果表明，催乳素分泌增加与短日照诱导的睾丸退化无关，而仅与长日照诱导的光不应性有关。
