Inhibition of reproductive maturation and somatic growth of Fischer 344 rats by photoperiods shorter than L14:D10 and by gradually decreasing photoperiod
Inhibition of reproductive maturation and somatic growth of Fischer 344 rats by photoperiods shorter than L14:D10 and by gradually decreasing photoperiod
复制标题
DOI：
10.1095/biolreprod63.5.1525
复制
发表时间：
2000-11-01
影响因子：
3.6
通讯作者：
Galvez, ME
中科院分区：
文献类型：
--
作者：
Heideman, PD;Bierl, CK;Galvez, ME
光周期是温带哺乳动物繁殖的主要调节因子。实验室大鼠通常被认为是无光反应的，但年轻的雄性Fischer 344(F344)大鼠对8小时的短光周期有独特的强烈反应。在断奶时，大鼠从16h的光周期转换到14h的光周期，生殖发育和躯体生长速度都减慢。光周期为13小时的受精卵反应最强。F344大鼠的临界光周期可以定义为13.5h的光周期，但光周期小于或等于12.5h才能完全抑制生殖和体细胞生长。这表明，在一些实验室群体中标准的12h光周期将对这种普通大鼠品系的生殖成熟和生长速度产生显著影响。与出生时转入短光周期的F344幼鼠相比，F344幼鼠在模拟自然变化的减少光周期中经历了更大程度和更长时间的生殖发育延迟和生长速度下降。光周期的逐渐变化的影响在断奶后至少持续了12周。这表明年轻的雄性F344大鼠对光周期的反应将导致野生哺乳动物的功能性光周期反应。
Photoperiod is the major regulator of reproduction in temperate-zone mammals. laboratory rats are generally considered to be nonphotoresponsive, but young male Fischer 344 (F344) rats have a uniquely robust response to short photoperiods of 8 h of light. Rats transferred at weaning from a photoperiod of 16 h to photoperiods of < 14 h of light slowed in both reproductive development and somatic growth rate. Those in photoperiods < 13 h of tight underwent the strongest responses. The critical photoperiod of F344 rats can be defined as 13.5 h of light, but photoperiods of less than or equal to 12,5 h are required to fully suppress reproduction and somatic growth. This demonstrates that the 12-h photoperiod that is standard in some laboratory colonies would have significant effects on reproductive maturation and growth rate of this common rat strain. Young F344 rats in decreasing photoperiods that mimic natural change experienced delayed reproductive development and decreased growth rate to a greater extent and for a longer duration than those transferred at birth to a short photoperiod. The effects of gradual changes in photoperiod persisted for at least 12 wk after weaning. This indicates that young male F344 rats possess responses to photoperiod that would result in functional photoperiodism in a wild mammal.