Renfree Marilyn B, Fenelon Jane, Wijayanti Gratiana, Wilson Jean D, Shaw Geoffrey
Department of Zoology, The University of Melbourne, Victoria 3010, Australia.
Dev Biol. 2009 Oct 15;334(2):429-36. doi: 10.1016/j.ydbio.2009.07.040. Epub 2009 Aug 4.
In developing mammalian males, conversion of the Wolffian ducts into the epididymides and vasa deferentia depends on androgen secretion by the testes, whereas in females these ducts remain in a vestigial form or regress. However, there is continuing uncertainty whether the androgen needs to be delivered locally, either by diffusion from the adjacent testis or, by secretion into the lumen of the duct, or whether circulating androgens maintain and virilize the Wolffian ducts. To resolve this uncertainty, we transplanted either day 0-2 or day 8-9 post-partum testes beneath the flank skin of three groups of neonatal (days 0-1) female tammar wallabies, where they developed and secreted physiological levels of hormones. The Wolffian ducts of all these females were retained and had formed extensive epididymides when examined at days 25, 34 and 87 after birth. In the two older groups of females, sampled after the time of prostatic bud formation, the urogenital sinus was virilized and there was extensive prostatic development similar to that of normal males of the same age, showing that androgen secretion had occurred. Virilization of the Wolffian ducts occurred during an early but short-lived window of sensitivity. This study provides the first clear evidence that under physiological conditions virilization can be mediated by circulating androgen.
在发育中的雄性哺乳动物体内，中肾管转化为附睾和输精管依赖于睾丸分泌的雄激素，而在雌性动物中，这些管道则保持退化状态或逐渐退化。然而，目前仍不确定雄激素是需要通过从相邻睾丸扩散或分泌到管腔中进行局部输送，还是通过循环雄激素来维持中肾管并使其雄性化。为了解决这一不确定性，我们将产后0 - 2天或8 - 9天的睾丸移植到三组新生（0 - 1天）雌性袋貂的胁腹皮肤下，移植后的睾丸能够发育并分泌生理水平的激素。在出生后第25天、34天和87天检查时，所有这些雌性动物的中肾管都得以保留，并形成了广泛的附睾。在两组年龄稍大的雌性动物中，在前列腺芽形成时间之后进行取样，发现泌尿生殖窦发生了雄性化，并且有广泛的前列腺发育，类似于同龄正常雄性动物，这表明雄激素分泌已经发生。中肾管的雄性化发生在一个早期但短暂的敏感窗口期。这项研究提供了首个明确证据，即在生理条件下，雄性化可由循环雄激素介导。
