Pearl Christopher A, At-Taras Eeman, Berger Trish, Roser Janet F
Department of Animal Science, University of California, Davis, One Shields Avenue, Davis, California 95616, USA.
Reproduction. 2007 Oct;134(4):593-604. doi: 10.1530/REP-06-0239.
The study presented herein was designed to test the hypothesis that reduced endogenous estrogen in the boar alters efferent duct morphology, epididymal morphology, and steroid receptor expression. Twenty-eight littermate pairs of boars were treated with Letrozole, an aromatase inhibitor, or with vehicle from 1 week of age until castration at 2 through 8 months. Efferent ducts and epididymides were examined for morphological development and steroid receptor expression. Efferent duct morphology was not different between control and Letrozole-treated animals at any examined age. Androgen receptor (AR), estrogen receptor alpha (ERalpha), and beta (ERbeta) were expressed in the epithelial cells of the efferent ducts at all ages; expression was similar in control and treated animals. Morphological development of the caput and corpus was delayed in Letrozole-treated animals, but this delay was transient since morphology was similar between control and treated animals at 8 months. The cauda did not show a delay in development, but was more developed in treated animals at 2 months. AR, ERalpha, and ERbeta were expressed in all three epididymal regions; no difference was observed between control and treated animals. In summary, estrogen appears to be important for development of the epididymis; however, the cauda may be regulated differently than the caput and corpus. Results for the efferent ducts suggest that the normally high endogenous estrogens are not required for regulation of fluid reabsorption in the boar. It also suggests that any ER activation required for maintenance of efferent duct morphology and function is normal in Letrozole-treated boars.
公猪体内内源性雌激素减少会改变输出小管形态、附睾形态以及类固醇受体表达。28对同窝出生的公猪从1周龄开始至2至8月龄去势期间，分别用芳香化酶抑制剂来曲唑或赋形剂进行处理。对输出小管和附睾进行形态发育及类固醇受体表达检测。在任何检测年龄，对照动物和来曲唑处理动物的输出小管形态均无差异。雄激素受体（AR）、雌激素受体α（ERα）和β（ERβ）在各年龄段输出小管的上皮细胞中均有表达；对照动物和处理动物中的表达相似。来曲唑处理动物的附睾头和附睾体的形态发育延迟，但这种延迟是短暂的，因为在8月龄时对照动物和处理动物的形态相似。附睾尾未出现发育延迟，但在2月龄时处理动物的附睾尾发育更成熟。AR、ERα和ERβ在附睾的所有三个区域均有表达；对照动物和处理动物之间未观察到差异。总之，雌激素似乎对附睾发育很重要；然而，附睾尾的调节方式可能与附睾头和附睾体不同。输出小管的结果表明，公猪中正常情况下较高的内源性雌激素并非调节液体重吸收所必需。这也表明，来曲唑处理的公猪中，维持输出小管形态和功能所需的任何雌激素受体激活都是正常的。
