Shavali S S, Haldar C
Center of Advanced Study in Zoology, Banaras Hindu University, Varanasi, India.
J Neural Transm (Vienna). 1998;105(4-5):407-13. doi: 10.1007/s007020050066.
Effects of continuous light (CL; 24L:0D), continuous darkness (CD; 24D:0L) and pinealectomy (Px) were tested on pineal-thyroid-gonadal axis of a tropical seasonally breeding rodent, Funambulus pennanti during its sexually active reproductive phase (February-March). CL had no effect on pineal, thyroid and ovarian functions as judged by weight, plasma level of thyroxine (T4) and estradiol (E2). However, CD reduced significantly thyroid and ovarian weight and plasma T4, and E2 levels. Px was stimulatory for thyroid and ovarian functions under normal photoperiod, and under CL, Px significantly increased thyroid and ovarian weights with no observable changes in their hormonal levels. Px under CD condition prevented the reduction in thyroid and ovarian weights but the hormonal levels were increased. These results suggest that CD could be a effective stimulator for the pineal function and increased pineal activity in this mammal. The inhibitory effect of CD on thyroid and ovarian functions could be due to the increased pineal activity in term of induced melatonin by CD itself.
在热带季节性繁殖啮齿动物彭氏跳鼠处于性活跃繁殖期（2月至3月）时，测试了持续光照（CL；24小时光照：0小时黑暗）、持续黑暗（CD；24小时黑暗：0小时光照）和松果体切除（Px）对松果体 - 甲状腺 - 性腺轴的影响。从重量、血浆甲状腺素（T4）和雌二醇（E2）水平判断，CL对松果体、甲状腺和卵巢功能没有影响。然而，CD显著降低了甲状腺和卵巢重量以及血浆T4和E2水平。在正常光周期下，Px对甲状腺和卵巢功能有刺激作用，在CL条件下，Px显著增加了甲状腺和卵巢重量，但其激素水平没有明显变化。在CD条件下进行Px可防止甲状腺和卵巢重量的减轻，但激素水平会升高。这些结果表明，CD可能是该哺乳动物松果体功能的有效刺激物，且会增加松果体活性。CD对甲状腺和卵巢功能的抑制作用可能是由于CD本身诱导褪黑素导致松果体活性增加所致。
