Kelly K K, Goldman B D, Zucker I
Department of Psychology, University of California, Berkeley 94720.
Biol Reprod. 1994 Nov;51(5):1046-50. doi: 10.1095/biolreprod51.5.1046.
In Siberian hamsters, long and short durations of nightly melatonin secretion are associated with testicular regression and development, respectively; surprisingly, the absence of a nightly melatonin signal induced by pinealectomy is less effective than a short (4-6 h) melatonin duration for promoting gonadal development. We compared the patterns of serum FSH and prolactin concentrations underlying pinealectomy-induced and photostimulated testicular growth in juvenile hamsters. Pinealectomy in photoinhibited hamsters on Day 18 produced significant gonadal development compared to that in short-day controls by Day 23. By Day 28, however, testes weights of pinealectomized hamsters were significantly lower than those of intact hamsters transferred to a long photoperiod. Pinealectomy was associated with significant elevations in serum FSH and prolactin concentrations over baseline by Day 21, but peak values were attenuated compared with those induced by exposure to long days. FSH titers of pinealectomized animals were significantly lower than those of photostimulated animals between Days 21 and 30 but were significantly greater on Days 35 and 40; prolactin values were comparable in pinealectomized and photostimulated hamsters between Days 21 and 25 but were significantly lower in the former group thereafter. Blunted elevation of FSH and prolactin secretion may underlie the slower rates of gonadal maturation observed in pinealectomized, juvenile hamsters. The neuroendocrine systems of pinealectomized hamsters appear to be in a state intermediate between those characteristic of hamsters kept in long and in short day lengths.
在西伯利亚仓鼠中，夜间褪黑素分泌的长时间和短时间分别与睾丸退化和发育相关；令人惊讶的是，松果体切除诱导的夜间褪黑素信号缺失在促进性腺发育方面不如短（4 - 6小时）的褪黑素分泌持续时间有效。我们比较了幼年仓鼠松果体切除诱导的和光刺激诱导的睾丸生长过程中血清促卵泡激素（FSH）和催乳素浓度的变化模式。在第18天对光抑制的仓鼠进行松果体切除，与短日照对照组相比，到第23天产生了显著的性腺发育。然而，到第28天，松果体切除仓鼠的睾丸重量显著低于转移到长光照周期的完整仓鼠。到第21天，松果体切除与血清FSH和催乳素浓度相对于基线的显著升高有关，但与长日照诱导的峰值相比有所减弱。在第21天至30天之间，松果体切除动物的FSH滴度显著低于光刺激动物，但在第35天和40天显著更高；在第21天至25天之间，松果体切除和光刺激仓鼠的催乳素值相当，但此后前一组显著更低。FSH和催乳素分泌的升高减弱可能是松果体切除的幼年仓鼠性腺成熟速度较慢的原因。松果体切除仓鼠的神经内分泌系统似乎处于长日照和短日照仓鼠特征状态之间的中间状态。
