Watson J T, Abdelnabi M, Wersinger S, Ottinger M A, Adkins-Regan E
Department of Psychology, Cornell University, Ithaca, New York 14853.
Gen Comp Endocrinol. 1990 Feb;77(2):229-38. doi: 10.1016/0016-6480(90)90307-8.
Previous experiments using systemic and preoptic area (POA) hormone treatments have shown that aromatization of testosterone (T) to estrogen (E) is essential for activation of male-typical copulatory behavior in castrated male Japanese quail (Coturnix japonica). Two experiments were conducted to determine whether circulating estrogen levels characteristic of normal intact males are high enough to activate male-typical or female-typical copulatory behavior. In Experiment 1, blood samples were drawn every 4 hr from groups of sexually active male quail housed under a 16L:8D light-dark cycle, and assayed for estradiol (E2) concentration. The mean +/- SEM serum E2 was 54.2 +/- 3.6 pg/ml, and no daily cycle in serum E2 was seen. The males were then tested for sexual behavior; 88% mounted females, and 23% crouched when mounted by males. In Experiment 2, 51 males were castrated and implanted with Silastic tubes containing estradiol benzoate (EB) and/or cholesterol designed to produce five different levels of serum E2, then tested for male- and female-typical copulatory behavior and bled. The serum E2 in EB-implanted quail which mounted (253 +/- 30 pg/ml) was significantly higher than that of intact quail in Experiment 1, and only 10.2% of intact males had serum E2 as high as the minimum associated with mounting in EB-implanted males. These results show that serum E2 levels in intact males are not high enough to support male-typical copulation, and that aromatization in the POA to produce locally high E2 levels may be required. In addition, it was found that the threshold serum E2 to elevate receptivity significantly was 3.6 times the intact male level, and only slightly higher than serum E2 reported for intact females. Thus the lack of receptivity in intact males is probably due to insufficient circulating E2, and the male is not defeminized with respect to sensitivity to E2 for activation of receptivity.
先前使用全身和视前区（POA）激素处理的实验表明，睾酮（T）向雌激素（E）的芳香化作用对于去势雄性日本鹌鹑（Coturnix japonica）的雄性典型交配行为的激活至关重要。进行了两项实验以确定正常完整雄性所特有的循环雌激素水平是否高到足以激活雄性典型或雌性典型的交配行为。在实验1中，每隔4小时从处于16小时光照：8小时黑暗光暗循环条件下的性活跃雄性鹌鹑组中采集血样，并测定雌二醇（E2）浓度。平均±标准误血清E2为54.2±3.6 pg/ml，未观察到血清E2的每日周期变化。然后对这些雄性进行性行为测试；88%的雄性骑跨雌性，23%的雄性在被其他雄性骑跨时蹲伏。在实验2中，对51只雄性进行去势，并植入含有苯甲酸雌二醇（EB）和/或胆固醇的硅橡胶管，设计使其产生五种不同水平的血清E2，然后对其进行雄性和雌性典型交配行为测试并采血。骑跨的植入EB的鹌鹑的血清E2（253±30 pg/ml）显著高于实验1中的完整鹌鹑，并且只有10.2%的完整雄性的血清E2达到与植入EB的雄性骑跨相关的最低水平。这些结果表明，完整雄性的血清E2水平不足以支持雄性典型交配，可能需要在POA中进行芳香化作用以产生局部高E2水平。此外，发现显著提高接受性的血清E2阈值是完整雄性水平的3.6倍，仅略高于完整雌性报道的血清E2水平。因此，完整雄性缺乏接受性可能是由于循环E2不足，并且雄性在对E2激活接受性的敏感性方面未被雌性化。
