Leska A, Kiezun J, Kaminska B, Dusza L
Department of Animal Physiology, University of Warmia and Mazury in Olsztyn, 10-719 Olsztyn, Poland.
Department of Animal Physiology, University of Warmia and Mazury in Olsztyn, 10-719 Olsztyn, Poland.
Domest Anim Endocrinol. 2015 Apr;51:96-104. doi: 10.1016/j.domaniend.2014.12.002. Epub 2014 Dec 11.
Seasonal fluctuations in the activity of bird testes are regulated by a complex mechanism where androgens play a key role. Until recently, the role played by estrogens in males has been significantly underestimated. However, there is growing evidence that the proper functioning of the testes is associated with optimal estradiol (E2) concentration in both the plasma and testes of many mammalian species. Estrogens are gradually emerging as very important players in hormonal regulation of reproductive processes in male mammals. Despite the previously mentioned, it should be noted that estrogenic action is limited by the availability of specific receptors--estrogen receptor alpha (ERα) and estrogen receptor beta (ERβ). Interestingly, there is a general scarcity of information concerning the estrogen responsive system in the testes of male birds, which is of particular interest in exploring the phenomenon of seasonality of reproduction. To address this question, we have investigated for the first time the simultaneous expression of testicular ERα and ERβ genes and proteins with the accompanying plasma and testicular E2 concentrations during the annual reproductive cycle of male bird. The research model was the domestic goose (Anser anser f. domestica), a species whose annual reproductive cycle can be divided into 3 distinct phases characterized by changes in testicular activity. It has been revealed that the stable plasma E2 profile did not correspond to changing intratesticular E2 profile throughout the experiment. The expression of ERα and ERβ genes and proteins was detected in gander testes and it fluctuated on a seasonal basis with lower level in breeding and sexual reactivation stages and higher level during the nonbreeding stage. Our results demonstrated changes in testicular sensitivity to estrogens in male domestic goose during the annual reproductive cycle. The seasonal pattern of estrogen receptors (ERs) expression was analyzed against the hormonal background and a potential mechanism of ERs regulation in bird testes was proposed. The present study revealed seasonal variations in the estrogen responsive system, but further research is needed to fully explore the role of estrogens in the reproductive tract of male birds.
鸟类睾丸活动的季节性波动受一种复杂机制调控，雄激素在其中起关键作用。直到最近，雌激素在雄性中的作用一直被严重低估。然而，越来越多的证据表明，许多哺乳动物物种的睾丸正常功能与血浆和睾丸中最佳雌二醇（E2）浓度相关。雌激素正逐渐成为雄性哺乳动物生殖过程激素调节中非常重要的参与者。尽管有上述情况，但应注意雌激素作用受特定受体——雌激素受体α（ERα）和雌激素受体β（ERβ）可用性的限制。有趣的是，关于雄性鸟类睾丸中雌激素反应系统的信息普遍匮乏，这在探索繁殖季节性现象方面尤为引人关注。为解决这个问题，我们首次研究了雄性鸟类年度繁殖周期中睾丸ERα和ERβ基因及蛋白质的同时表达以及伴随的血浆和睾丸E2浓度。研究模型是家鹅（Anser anser f. domestica），该物种的年度繁殖周期可分为3个不同阶段，其特征是睾丸活动发生变化。研究发现，在整个实验过程中，稳定的血浆E2水平与睾丸内变化的E2水平并不对应。在雄鹅睾丸中检测到了ERα和ERβ基因及蛋白质的表达，其表达随季节波动，在繁殖和性重新激活阶段水平较低，在非繁殖阶段水平较高。我们的结果表明，雄性家鹅在年度繁殖周期中睾丸对雌激素的敏感性发生了变化。针对激素背景分析了雌激素受体（ERs）表达的季节性模式，并提出了鸟类睾丸中ERs调节的潜在机制。本研究揭示了雌激素反应系统的季节性变化，但仍需进一步研究以充分探索雌激素在雄性鸟类生殖道中的作用。
