Sexual differentiation of the copulatory neuromuscular system in green anoles (Anolis carolinensis): normal ontogeny and manipulation of steroid hormones.
Sexual differentiation of the copulatory neuromuscular system in green anoles (Anolis carolinensis): normal ontogeny and manipulation of steroid hormones.
复制标题
绿安乐蜥（Anolis carolinensis）交配神经肌肉系统的性别分化：正常个体发育和类固醇激素的操纵。
DOI：
10.1002/cne.20645
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发表时间：
2005
期刊：
影响因子：
--
通讯作者：
Wade,Juli
中科院分区：
文献类型：
--
作者：
Holmes,MelissaM;Wade,Juli
The copulatory neuromuscular system of green anoles is sexually dimorphic and differentiates during embryonic development, although details of the process were unknown. In Experiment 1, we determined the time course of normal ontogeny. Both male and female embryos possessed bilateral copulatory organs (hemipenes) and associated muscles until incubation day 13; the structures completely regressed in female embryos by incubation day 19 (total incubation 34 days). In Experiment 2, we treated eggs with testosterone, dihydrotestosterone, estradiol, or vehicle on both incubation days 10 and 13 to determine whether these steroid hormones mediate sexual differentiation. These time points fall between gonadal differentiation, which was determined in Experiment 1 to complete before day 10, and regression of the peripheral copulatory system in females. Tissue was collected on the day of hatching. Gonads were classified as testes or ovaries; presence versus absence of hemipenes and muscles, and the number and size of copulatory motoneurons were determined. Copulatory system morphology of vehicle‐treated animals matched their gonadal sex. Hemipenes and muscles were absent in estradiol‐treated animals, and androgens rescued the hemipenes and muscles in most females. Both testosterone and dihydrotestosterone treatment also caused hypertrophy of the hemipenes, which were everted in animals treated with these steroids. Copulatory motoneurons, assessed on the day of hatching in both experiments, were not dimorphic in size or number. Steroid treatment significantly increased motoneuron size and number overall, but no significant differences were detected in pairwise comparisons. These data demonstrate that differentiation of peripheral copulatory neuromuscular structures occurs during embryonic development and is influenced by gonadal steroids (regression by estradiol and enhancement by androgens), but associated motoneurons do not differentiate until later in life. J. Comp. Neurol. 489:480–490, 2005. © 2005 Wiley‐Liss, Inc.
