Paul Matthew J, Park Jin Ho, Horton Teresa H, Alvarez Maria I, Burke Morgan K, Place Ned J, Zucker Irving
Department of Psychology, University of California, CA 94720, USA.
Biol Reprod. 2006 Aug;75(2):261-9. doi: 10.1095/biolreprod.106.050781. Epub 2006 May 17.
In mammals, removal of one testis results in compensatory testicular hypertrophy (CTH) of the remaining gonad. Although CTH is ubiquitous among juveniles of many species, laboratory rats, laboratory mice, and humans unilaterally castrated in adulthood fail to display CTH. We documented CTH in pre- and postpubertally hemi-castrated Syrian and Siberian hamsters and tested whether day length affects CTH in juvenile and adult Siberian hamsters. Robust CTH was evident in long-day hemi-castrates of both species and was preceded by increased serum FSH concentrations in juvenile Siberian hamsters. In sharp contrast, CTH was undetectable in short-day hemi-castrated Siberian hamsters for several months and only made its appearance with the development of neuroendocrine refractoriness to short day lengths; serum FSH concentrations of juveniles also did not increase above sham-castrate values until the onset of refractoriness. Long-day hemi-castrated Siberian hamsters with hypertrophied testes underwent complete gonadal regression after transfer to short days, albeit at a reduced rate for the first 3 weeks of treatment. Blood testosterone concentrations of adult hamsters did not differ between long-day hemicastrates and sham-castrates 9-12 weeks after surgery. We conclude that CTH is suppressed by short day lengths in Siberian hamsters at all ages and stages of reproductive development; in short day lengths, but not long day lengths, the remaining testis produces sufficient negative feedback inhibition to restrain FSH hypersecretion and prevent CTH.
在哺乳动物中，摘除一侧睾丸会导致剩余性腺出现代偿性睾丸肥大（CTH）。尽管CTH在许多物种的幼体中普遍存在，但成年后接受单侧阉割的实验室大鼠、实验室小鼠和人类并未表现出CTH。我们记录了青春期前后半阉割的叙利亚仓鼠和西伯利亚仓鼠的CTH情况，并测试了日照长度是否会影响幼年和成年西伯利亚仓鼠的CTH。在两种仓鼠的长日照半阉割组中均出现了明显的CTH，且幼年西伯利亚仓鼠在CTH出现之前血清促卵泡激素（FSH）浓度升高。形成鲜明对比的是，短日照半阉割的西伯利亚仓鼠在几个月内未检测到CTH，直到对短日照长度产生神经内分泌不应性时才出现；幼年仓鼠的血清FSH浓度在不应性开始之前也未升高至假阉割组以上水平。长日照半阉割且睾丸肥大的西伯利亚仓鼠在转移到短日照环境后性腺完全退化，尽管在治疗的前3周退化速度较慢。成年仓鼠术后9 - 12周，长日照半阉割组和假阉割组的血液睾酮浓度没有差异。我们得出结论，在西伯利亚仓鼠生殖发育的所有年龄和阶段，短日照长度都会抑制CTH；在短日照而非长日照条件下，剩余的睾丸会产生足够的负反馈抑制作用，以抑制FSH分泌过多并防止CTH的发生。
