Schlatt S, De Geyter M, Kliesch S, Nieschlag E, Bergmann M
Institute of Reproductive Medicine of the University, Münster, Germany.
Biol Reprod. 1995 Nov;53(5):1169-77. doi: 10.1095/biolreprod53.5.1169.
Photosensitive rodents exposed to inhibitory short photoperiods become insensitive to this environmental factor after prolonged exposure. During the following process of spontaneous recrudescence, the animals that have adapted to the winter season show a return of all seasonal parameters. In the Djungarian hamster, obvious photoperiod-dependent changes are reinitiation of the reproductive organs, a 20-30% increase in body weight, and a moult from whitish fur into brown summer fur. This study was designed to analyze the morphological and endocrinological changes occurring during spontaneous testicular recrudescence in male Djungarian hamsters under prolonged short photoperiods. Two experiments were performed 1) to analyze the time-dependent changes in groups of hamsters exposed to short photoperiods and 2) to observe testicular and humoral changes in individual animals during spontaneous recrudescence. Regrowth of the testes and seminal vesicles did not begin before Week 18 in short photoperiods. While serum testosterone did not increase before Week 24, serum FSH had already returned to normal values from Week 18 onwards. Individual analysis by enzyme histochemistry revealed that 3 beta-hydroxysteroid-dehydrogenase activity in Leydig cells was not restored before testicular weights of more than 400 mg were observed and the first wave of spermatogenesis had reached the stage of elongated spermatids. This indicates that the testicular testosterone production was low until a status of testicular recrudescence had been achieved, at which point the testis showed complete qualitative spermatogenesis and a restoration of the Sertoli cell actin filaments. These data suggest that the process of early spontaneous recrudescence in male Djungarian hamsters appears to be initiated by the restoration of serum FSH rather than by testosterone.
暴露于抑制性短光照周期的光敏啮齿动物在长时间暴露后会对这种环境因素变得不敏感。在随后的自发恢复过程中，适应冬季的动物所有季节性参数都会恢复。在中仓鼠中，明显的光周期依赖性变化包括生殖器官的重新启动、体重增加20 - 30%以及从白色皮毛换成棕色夏毛。本研究旨在分析在长时间短光照周期下雄性中仓鼠自发睾丸恢复过程中发生的形态学和内分泌学变化。进行了两个实验：1）分析暴露于短光照周期的仓鼠组随时间的变化；2）观察个体动物在自发恢复过程中的睾丸和体液变化。在短光照周期下，睾丸和精囊的再生直到第18周才开始。虽然血清睾酮在第24周前没有增加，但血清促卵泡激素从第18周起就已恢复到正常水平。通过酶组织化学进行的个体分析显示，在观察到睾丸重量超过400毫克且第一波精子发生达到延长精子细胞阶段之前，睾丸间质细胞中的3β - 羟基类固醇脱氢酶活性没有恢复。这表明在达到睾丸恢复状态之前，睾丸睾酮生成较低，此时睾丸显示出完全的定性精子发生以及支持细胞肌动蛋白丝的恢复。这些数据表明，雄性中仓鼠早期自发恢复过程似乎是由血清促卵泡激素的恢复而非睾酮启动的。
