Veney Sean L, Wade Juli
Neuroscience Program, Michigan State University, East Lansing, MI 48824, USA.
Gen Comp Endocrinol. 2004 Apr;136(2):192-9. doi: 10.1016/j.ygcen.2003.12.017.
The zebra finch syrinx (sound production organ) is a sexually dimorphic component of the song system. Only male zebra finches sing, and in parallel, the overall mass and size of fibers in the two largest syrinx muscles are greater in males than females. Despite these obvious sexual dimorphisms, little is known about the role of steroid hormones in the maintenance of the structure and/or function of the syrinx. In this report, we used in situ hybridization to assess the expression of androgen receptor (AR), estrogen receptor alpha (ERalpha), and aromatase (AROM) mRNAs in the syrinx of adult male and female zebra finches. Increased AR mRNA expression was noted in males compared to females in two regions, over the ventralis muscle and in a band of connective tissue neighboring cartilage (perichondria). In contrast, we did not detect specific ERalpha or AROM mRNA expression within the syrinx. However, substantial ERalpha mRNA was present in oviduct, and aromatase mRNA was expressed at high levels in ovary. In parallel, an assay for AROM detected activity in ovary, but not in syrinx tissue from males or females. Taken together, these data suggest that the adult syrinx is sensitive to androgens; that sex differences in function and morphology of the syrinx may in part be due to increased expression of AR in males compared to females. In contrast, estrogen receptor alpha and AROM appear to have limited roles.
斑胸草雀的鸣管（发声器官）是鸣唱系统中具有性别二态性的组成部分。只有雄性斑胸草雀会唱歌，与此同时，雄性鸣管中两块最大肌肉的纤维总体质量和大小都比雌性的更大。尽管存在这些明显的性别二态性，但关于类固醇激素在维持鸣管结构和/或功能方面的作用却知之甚少。在本报告中，我们使用原位杂交技术来评估成年雄性和雌性斑胸草雀鸣管中雄激素受体（AR）、雌激素受体α（ERα）和芳香化酶（AROM）mRNA的表达情况。与雌性相比，在两个区域（腹侧肌上方以及与软骨相邻的结缔组织带（软骨膜））中，雄性的AR mRNA表达增加。相比之下，我们在鸣管内未检测到特异性的ERα或AROM mRNA表达。然而，输卵管中存在大量的ERα mRNA，且卵巢中芳香化酶mRNA的表达水平很高。与此同时，一项针对AROM的检测在卵巢中检测到了活性，但在雄性或雌性的鸣管组织中未检测到。综合这些数据表明，成年鸣管对雄激素敏感；鸣管在功能和形态上的性别差异可能部分归因于雄性与雌性相比AR表达的增加。相比之下，雌激素受体α和芳香化酶似乎作用有限。
