Balthazart J, Schumacher M, Malacarne G
Physiol Behav. 1985 Aug;35(2):157-66. doi: 10.1016/0031-9384(85)90330-0.
A series of 4 experiments was performed to study the relative contribution of androgens and estrogens in the activation of sexual behavior in castrated male quail. The synthetic androgen methyltrienolone (R 1881) which is not metabolized in androgen target tissues activated sexual behavior in castrated birds and at the dose level of 0.5-1 mg/day/animal had the same potency as testosterone (T). However R 1881 was much more active than T in the induction of cloacal gland growth and activation of crowing, two typically androgen-dependent responses. This suggests that sexual behavior is not controlled by exactly the same mechanism as crowing or cloacal gland growth. In another experiment, estradiol (E2) alone activated sexual behavior but it is only at very high doses which had clear toxic effects that a significant behavioral activation could be observed. This questions the role of E2 as the physiological agent stimulating copulation in intact birds unless it is assumed that centrally administered E2 would be much more active compared to peripheral E2 which is exposed to a very intense peripheral catabolism. In the last two experiments, a clear synergism could be detected between 5 alpha-dihydrotestosterone (5 alpha-DHT) and E2 in the activation of sexual activity and doses of hormones could be defined which had almost no activity by themselves but significantly stimulated sexual behavior when given simultaneously. It was however impossible to define a hormonal treatment with T metabolites which restored behavior to its precastration level, a result very easily achieved with T treatments. Taken together, these data suggest that activation of sexual behavior in quail does not depend only on E2, nor 5 alpha-DHT nor even on their combined action. Considering that specific T receptors which probably do not bind 5 alpha-DHT are present in the brain, it would seem justified to reconsider the possible role played by T itself in the activation of behavior.
进行了一系列4个实验，以研究雄激素和雌激素在去势雄性鹌鹑性行为激活中的相对作用。合成雄激素甲基三烯醇酮（R 1881）在雄激素靶组织中不被代谢，可激活去势鸟类的性行为，在剂量为0.5 - 1毫克/天/动物时，其效力与睾酮（T）相同。然而，R 1881在诱导泄殖腔腺生长和鸣叫激活方面比T活跃得多，这两种反应是典型的雄激素依赖性反应。这表明性行为的控制机制与鸣叫或泄殖腔腺生长不完全相同。在另一个实验中，单独的雌二醇（E2）可激活性行为，但只有在非常高的剂量下（这些剂量有明显的毒性作用）才能观察到显著的行为激活。这对E2作为完整鸟类中刺激性交的生理因子的作用提出了质疑，除非假定中枢给予的E2与暴露于非常强烈的外周分解代谢的外周E2相比会更活跃。在最后两个实验中，在性活动激活方面，5α - 双氢睾酮（5α - DHT）和E2之间可检测到明显的协同作用，并且可以确定单独几乎没有活性但同时给予时能显著刺激性行为的激素剂量。然而，无法用睾酮代谢物确定一种能将行为恢复到去势前水平的激素处理方法，而用睾酮处理很容易达到这个结果。综上所述，这些数据表明鹌鹑性行为的激活不仅不依赖于E2，也不依赖于5α - DHT，甚至不依赖于它们的联合作用。考虑到大脑中存在可能不结合5α - DHT的特定睾酮受体，重新考虑睾酮本身在行为激活中可能发挥的作用似乎是合理的。
