Neal Jennifer K, Wade Juli
Michigan State University, Neuroscience Program, 108 Giltner Hall, East Lansing, MI 48824, USA.
Horm Behav. 2007 Aug;52(2):228-36. doi: 10.1016/j.yhbeh.2007.04.009. Epub 2007 May 4.
Investigating individual differences in sexual performance in unmanipulated males is important for understanding natural relationships between behavior and morphology, and the mechanisms regulating them. Among male green anole lizards, some court and copulate frequently (studs) and others do not (duds). To evaluate potential factors underlying differences in the level of these behaviors, morphology and androgen receptor expression in neuromuscular courtship and copulatory structures, as well as in the preoptic area and amygdala, were compared in males displaying varying degrees of sexual function. This study revealed that individual differences in behavior among unmanipulated males, in particular the extension of a throat fan (dewlap) used during courtship, were positively correlated with the size of fibers in the associated muscle and with soma size in the amygdala. The physiological response to testosterone, as indicated by the height of cells in an androgen-sensitive portion of the kidney, was also correlated with male sexual behavior, and predicted it better than plasma androgen levels. Androgen receptor expression was not related to the display of courtship or copulation in any of the tissues examined. The present data indicate that higher levels of male courtship behavior result in (or are the result of) enhanced courtship muscle and amygdala morphology, and that androgen-sensitive tissue in studs may be more responsive to testosterone than duds. However, some mechanism(s) other than androgen receptor expression likely confer this difference in responsiveness.
研究未受干预的雄性个体在性行为表现上的个体差异，对于理解行为与形态之间的自然关系以及调节它们的机制非常重要。在雄性绿安乐蜥中，一些个体频繁求偶和交配（活跃者），而另一些则不然（不活跃者）。为了评估这些行为水平差异背后的潜在因素，对具有不同性功能程度的雄性个体的神经肌肉求偶和交配结构以及视前区和杏仁核中的形态和雄激素受体表达进行了比较。这项研究表明，未受干预的雄性个体之间的行为个体差异，特别是求偶期间使用的喉部扇状物（喉扇）的伸展，与相关肌肉中的纤维大小以及杏仁核中的体细胞大小呈正相关。肾脏雄激素敏感部分细胞的高度所表明的对睾酮的生理反应，也与雄性性行为相关，并且比血浆雄激素水平更能预测性行为。在所检查的任何组织中，雄激素受体表达与求偶或交配表现均无关。目前的数据表明，较高水平的雄性求偶行为导致（或源于）求偶肌肉和杏仁核形态的增强，并且活跃者中的雄激素敏感组织可能比不活跃者对睾酮更敏感。然而，除了雄激素受体表达之外的某些机制可能导致这种反应性差异。
