Department of Biological Sciences, The University of Southern Mississippi, 118 College Drive # 5018, Hattiesburg, MS 39406, USA.
Gen Comp Endocrinol. 2011 Dec 1;174(3):370-8. doi: 10.1016/j.ygcen.2011.09.016. Epub 2011 Oct 1.
Yearly, testosterone (T) levels fluctuate as many vertebrates cycle through reproductive and non-reproductive periods. Among many temperate birds, it is well established that levels of T peak as gonads recrudesce for breeding and then fall as gonads regress prior to the non-breeding season. While the tissues producing breeding season T are well studied, the tissues responsible for non-breeding T have received less investigative attention. We examined the ability of male and female Northern Cardinals (Cardinalis cardinalis) to elevate gonadal T following standardized injections of gonadotropin-releasing hormone (GnRH) across three non-breeding seasons. Males and females were capable of significantly elevating gonadal T production following GnRH injections during periods of reproductive quiescence. The magnitude of T elevation varied across the non-breeding season, but not between sexes. To our knowledge, this is the first report of a significant increase in gonadal T production following GnRH injections administered in the non-breeding season.
每年，许多脊椎动物都会经历繁殖期和非繁殖期，从而导致睾酮（T）水平波动。在许多温带鸟类中，已经确定 T 水平在繁殖期性腺恢复时达到峰值，然后在非繁殖期性腺退化前下降。虽然产生繁殖季节 T 的组织已经得到了很好的研究，但负责非繁殖季节 T 的组织受到的关注较少。我们在三个非繁殖季节中检查了雄性和雌性红衣主教（Cardinalis cardinalis）在接受促性腺激素释放激素（GnRH）标准化注射后升高性腺 T 的能力。在繁殖静止期，雄性和雌性在 GnRH 注射后均能显著升高性腺 T 的产生。T 升高的幅度在非繁殖季节有所不同，但性别间无差异。据我们所知，这是首次在非繁殖季节注射 GnRH 后报告性腺 T 产量显著增加。
