Mendonça M T, Licht P
J Exp Zool. 1986 Jul;239(1):117-30. doi: 10.1002/jez.1402390114.
A series of photothermal treatments was initiated at different times of year to examine the relative contributions of exogenous and endogenous factors affecting the timing of the testicular cycle of the kinosternid turtle, Sternotherus odoratus. Elevated temperature appeared to be the major factor stimulating testicular recrudescence (spermatocytogenesis, spermiogenesis, and, to some extent, androgen secretion). However, depending on the time of year, short or long daylengths, in conjunction with elevated temperatures, enhanced testicular responses (recrudescence or regression). Also, high temperatures are not requisite for recrudescence. Spermatogenic activity and testis growth differ in their temperature sensitivity and may become dissociated, and an endogenous mechanism may have affected peak androgen secretion. Testicular regression exhibited a dependence on an interaction among temperature, photoperiod, and endogenous regulation. Turtles with testes in advanced stages of spermiogenesis underwent accelerated regression when exposed to even slightly reduced temperatures, especially at short daylengths. However, regression was delayed by a combination of high temperature and short daylength in fall. Results are compared to other experimental studies of photothermal effects on turtles and discussed in terms of the described latitudinal variations in the timing of the testicular cycle of S. odoratus.
在一年中的不同时间开始进行一系列光热治疗，以研究影响动胸龟（麝香龟，Sternotherus odoratus）睾丸周期时间的外源性和内源性因素的相对作用。温度升高似乎是刺激睾丸再发育（精母细胞发生、精子发生以及在一定程度上雄激素分泌）的主要因素。然而，根据一年中的时间不同，短日照或长日照与升高的温度相结合，会增强睾丸反应（再发育或退化）。此外，再发育并不一定需要高温。生精活动和睾丸生长在温度敏感性方面存在差异，可能会出现分离，并且一种内源性机制可能影响雄激素分泌峰值。睾丸退化表现出对温度、光周期和内源性调节之间相互作用的依赖性。处于精子发生后期的睾丸的龟，当暴露于即使稍有降低的温度下，尤其是在短日照时，会经历加速退化。然而，在秋季，高温和短日照的组合会延迟退化。将结果与其他关于光热对龟影响的实验研究进行了比较，并根据麝香龟睾丸周期时间中所描述的纬度变化进行了讨论。
