Neuroscience Program, Michigan State University, East Lansing, MI 48824-1101, United States.
Gen Comp Endocrinol. 2013 Nov 1;193:56-67. doi: 10.1016/j.ygcen.2013.07.006. Epub 2013 Jul 24.
Green anoles are seasonally breeding lizards, with an annual rise in testosterone (T) being the primary activator of male sexual behaviors. Responsiveness to T is decreased in the non-breeding season (NBS) compared to breeding season (BS) on a variety of levels, including displays of reproductive behavior and the morphology and biochemistry of associated tissues. To evaluate the possibility that seasonal changes in responsiveness to T are regulated by androgen receptors (AR) and/or two of its coactivators, CREB binding protein (CBP) and steroid receptor coactivator-1 (SRC-1), we tested whether they differ in expression across season in brains of both sexes and in peripheral copulatory tissues of males (hemipenis and retractor penis magnus muscle). AR mRNA was increased in the brains of males compared to females and in copulatory muscle in the BS compared to NBS. In the hemipenis, transcriptional activity appeared generally diminished in the NBS. T-treatment increased AR mRNA in the copulatory muscle and AR protein in the hemipenis, the latter to a greater extent in the BS than the NBS. T also decreased SRC-1 protein in hemipenis. Interpretations are complicated, in part because levels of mRNA and protein expression were not correlated and multiple sizes of the AR and CBP proteins were detected, with some tissue specificity. However, the results are consistent with the idea that differences in receptor and coactivator expression at central and peripheral levels may play roles in regulating sex and seasonal differences in the motivation or physical ability to engage in sexual behavior.
绿安乐蜥是季节性繁殖的蜥蜴，睾丸酮（T）的年度增长是雄性性行为的主要激活剂。与繁殖季节（BS）相比，非繁殖季节（NBS）在各种水平上对 T 的反应性降低，包括生殖行为的表现以及相关组织的形态和生物化学。为了评估对 T 的反应性的季节性变化是否受雄激素受体（AR）和/或其两种共激活剂，CREB 结合蛋白（CBP）和类固醇受体共激活剂-1（SRC-1）调节的可能性，我们测试了它们在两性大脑中和雄性交配组织（半阴茎和阴茎大退缩肌）中的表达是否随季节而变化。与雌性相比，雄性大脑中的 AR mRNA 增加，BS 中比 NBS 中在交配肌肉中的增加。在半阴茎中，转录活性在 NBS 中普遍降低。T 处理增加了交配肌肉中的 AR mRNA 和半阴茎中的 AR 蛋白，BS 中的增加程度大于 NBS。T 还减少了半阴茎中的 SRC-1 蛋白。解释比较复杂，部分原因是 mRNA 和蛋白表达水平没有相关性，并且检测到 AR 和 CBP 蛋白的多种大小，具有一定的组织特异性。然而，结果与以下观点一致，即中枢和外周水平的受体和共激活剂表达的差异可能在调节性和季节性差异的性行为动机或进行性行为的身体能力中发挥作用。
