Hormones and sex differences in the musk shrew

描述（由申请人提供）：类固醇激素是导致许多物种（包括人类）大脑和行为中观察到的性别差异的原因。雌性亚洲麝香鼩（Suncus murinus）是一种食虫动物，与大多数其他哺乳动物不同的是：1）缺乏行为发情周期; 2）卵巢持续释放睾酮，而不是雌激素或孕酮。我们发现，麝香鼩的性别分化方面更接近灵长类动物的模式，而不是更常见的研究动物，如大鼠和小鼠。我们建议检查性别差异和激素控制的发展和显示的几个性二型行为在这个物种，包括交配行为和空间学习。我们将研究发育激素在性分化中的作用，方法是用睾酮及其主要代谢产物对雌性动物进行生殖治疗，然后研究成年期的性二态行为和相关的脑结构。我们希望在一个很少研究的哺乳动物秩序的基础研究的身体，而在同一时间为学生在我们的小女子文理学院提供了宝贵的研究经验，这将提高他们的实验室技能，并提供必要的培训，在研究生课程和研究相关的职业生涯取得成功。在性行为的调节方面，麝香鼩与通常研究的啮齿类动物不同，但与灵长类动物（包括人类）有某些相似之处：1）雌性在发情期以外的时间交配; 2）发育中的睾酮不需要转化为雌激素来塑造雄性典型的性行为;性兴趣在性腺成熟之前发展，可能是在肾上腺雄激素的影响下。由于灵长类动物的基础研究是昂贵的，耗时的，而且往往是不切实际的，我们建议在一个物种中开发一种替代的小动物模型，它可能比大鼠和小鼠更接近人类。我们相信，性分化的动物模型将有助于了解性腺激素如何塑造发育中的人类大脑，并影响日后生活中可观察到的性别差异。

DESCRIPTION (provided by applicant): Steroid hormones are responsible for many observed sex differences in brain and behavior in a variety of species, including humans. The female Asian musk shrew (Suncus murinus) is an insectivore that differs from most other mammals in its 1) lack of behavioral estrus cycle and 2) continuous testosterone release by the ovaries, rather than estrogen or progesterone. We have found that aspects of musk shrew sexual differentiation more closely resemble the pattern found in primates than that in more commonly studied animals like rats and mice. We propose to examine sex differences and hormonal control of the development and display of several sexually dimorphic behaviors in this species, including copulatory behaviors and spatial learning. We will investigate the role of developmental hormones in sexual differentiation by treating females neonatally with testosterone and its major metabolites, then examining sexually dimorphic behaviors and related brain structures in adulthood. We hope to add to the body of basic research in a rarely-studied mammalian order while at the same time provide students in our small women's liberal arts college with a valuable research experience that will enhance their laboratory skills and provide training necessary for success in graduate programs and research-related careers. (RELEVANCE TO PUBLIC HEALTH) In the regulation of sexual behavior, the musk shrew differs from commonly studied rodents but shares certain similarities with primates, including humans: 1) females mate at times other than a distinct estrus period; 2) developmental testosterone does not require conversion to estrogen to shape male-typical sexual behavior; and 3) sexual interest develops prior to gonadal maturity, probably under the influence of adrenal androgens. Since basic research in primates is expensive, time-consuming and often otherwise impractical, we propose to develop an alternate small-animal model in a species that may more closely resemble humans than do rats and mice. We believe that an animal model for sexual differentiation will be useful to understanding how gonadal hormones shape the developing human brain and influence observable sex differences in later life.