Rhen Turk, Sakata Jon T, Crews David
Department of Biology, University of North Dakota, Grand Forks, 58202, USA.
Gen Comp Endocrinol. 2005 Jul;142(3):289-96. doi: 10.1016/j.ygcen.2005.01.018.
Incubation temperature during embryonic development determines gonadal sex in the leopard gecko (Eublepharis macularius). Incubation temperature and gonadal sex jointly influence the display of sexual and agonistic behavior in adult leopard geckos. These differences in adult behavior are organized prior to sexual maturity, and it is plausible that post-natal hormones influence neural and behavioral differentiation. Here we assessed incubation temperature and sex effects on sex steroid levels in leopard geckos at 2, 10, and 25 weeks of age and monitored the development of male secondary sex structures. Males had significantly higher androgen concentrations at all time points, whereas females had significantly higher 17beta-estradiol (E2) concentrations only at 10 and 25 weeks. Within males, age but not incubation temperature affected steroid levels and morphological development. Male androgen levels increased modestly by 10 and dramatically by 25 weeks of age, whereas E2 levels remained unchanged over this period. Most males had signs of hemipenes at 10 weeks of age, and all males had hemipenes and open preanal pores by 25 weeks of age. In females, age and incubation temperature affected E2 and dihydrotestosterone (DHT) but not T concentrations. Controlling for age, females from 34 degrees C have higher DHT and lower E2 levels than females from 30 degrees C. Further, E2 concentrations increased significantly from 2 to 10 weeks, after which E2 levels remained steady. Together, these results indicate that sexually dimorphic levels of steroids play a major role in the development of leopard gecko behavior and morphology. Furthermore, these data suggest that the organizational effects of incubation temperature on adult female phenotype could be, in part, mediated by incubation temperature effects on steroid hormone levels during juvenile development.
豹纹守宫（Eublepharis macularius）胚胎发育期间的孵化温度决定其性腺性别。孵化温度和性腺性别共同影响成年豹纹守宫的性行为和攻击行为表现。成年行为的这些差异在性成熟之前就已形成，产后激素影响神经和行为分化是有道理的。在此，我们评估了孵化温度和性别对2周、10周和25周龄豹纹守宫性类固醇水平的影响，并监测了雄性第二性征结构的发育。雄性在所有时间点的雄激素浓度均显著更高，而雌性仅在10周和25周时17β - 雌二醇（E2）浓度显著更高。在雄性中，年龄而非孵化温度影响类固醇水平和形态发育。雄性雄激素水平在10周时适度增加，在25周时显著增加，而在此期间E2水平保持不变。大多数雄性在10周龄时有半阴茎迹象，到25周龄时所有雄性都有半阴茎和开放的肛前孔。在雌性中，年龄和孵化温度影响E2和双氢睾酮（DHT）但不影响睾酮（T）浓度。在控制年龄的情况下，来自34摄氏度的雌性比来自30摄氏度的雌性具有更高的DHT和更低的E2水平。此外，E2浓度从2周显著增加到10周，此后E2水平保持稳定。总之，这些结果表明，类固醇的性别二态性水平在豹纹守宫行为和形态发育中起主要作用。此外，这些数据表明，孵化温度对成年雌性表型的组织效应可能部分是由孵化温度对幼体发育期间类固醇激素水平的影响介导的。
