Simulated natural day lengths synchronize seasonal rhythms of asynchronously born male Siberian hamsters
Simulated natural day lengths synchronize seasonal rhythms of asynchronously born male Siberian hamsters
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DOI：
10.1152/ajpregu.00146.2007
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发表时间：
2007-07-01
影响因子：
2.8
通讯作者：
Zucker, Irving
中科院分区：
文献类型：
--
作者：
Butler, Matthew P.;Turner, Kevin W.;Zucker, Irving
光周期研究依赖于静态的日长和长日与短日之间的突然转换来表征驱动季节节律的信号。为了确定生态相关的临界日长，并测试在何种程度上自然变化的日长同步重要的发育事件，我们监测了9个队列的雄性西伯利亚仓鼠（Photopus sungorus）出生每2周从4周前至12周后夏至在模拟自然光周期（SNP）。出生前4周至2周后的SNP仓鼠经历了快速的躯体和性腺生长;出生后4-6周至，一些延迟青春期许多周，而其他表现出青春期提前。出生在夏至后八周或更长时间的仓鼠无法进行早期睾丸发育。过渡到延迟发展发生在长日照，诱导青春期提前时，提出了静态光周期。第一批延迟青春期的动物可能主要是基于出生后日长的减少，而在后来的队列中，出生后日长与妊娠日长的比较可能有助于发育停滞。尽管出生时间和青春期时间存在差异，但在所有队列中，秋季性腺退化和春季性腺和躯体生长发生在相似的日历日期。逐渐变化的光周期施加强有力的组织效果的季节性节律，提供仓鼠的环境时间线索比简单的静态日长更丰富的来源。
Photoperiodism research has relied on static day lengths and abrupt transitions between long and short days to characterize the signals that drive seasonal rhythms. To identify ecologically relevant critical day lengths and to test the extent to which naturally changing day lengths synchronize important developmental events, we monitored nine cohorts of male Siberian hamsters (Phodopus sungorus) born every 2 wk from 4 wk before to 12 wk after the summer solstice in a simulated natural photoperiod (SNP). SNP hamsters born from 4 wk before to 2 wk after the solstice underwent rapid somatic and gonadal growth; among those born 4-6 wk after the solstice, some delayed puberty by many weeks, whereas others manifested early puberty. Hamsters born eight or more weeks after the solstice failed to undergo early testicular development. The transition to delayed development occurred at long day lengths, which induce early puberty when presented as static photoperiods. The first animals to delay puberty may do so predominantly on the basis of postnatal decreases in day length, whereas in later cohorts, a comparison of postnatal day length to gestational day length may contribute to arrested development. Despite differences in timing of birth and timing of puberty, autumn gonadal regression and spring gonadal and somatic growth occurred at similar calendar dates in all cohorts. Incrementally changing photoperiods exert a strong organizing effect on seasonal rhythms by providing hamsters with a richer source of environmental timing cues than are available in simple static day lengths.