Garg S K
Department of Zoology, Haryana Agricultural University, Hisar, India.
J Pineal Res. 1989;7(2):91-104. doi: 10.1111/j.1600-079x.1989.tb00658.x.
To investigate the relative importance of pineal, and eyes, and melatonin treatment on ovarian activity, catfish. Heteropneustes fossilis subjected to pinealectomy, eye enucleation, or both were exposed to short (LD 9:15) or long (LD 14:10) photoperiod during the different stages of the annual reproductive cycle. During the preparatory period, pinealectomy accelerated ovarian recrudescence under long photoperiod, but no effects of pinealectomy were observed under short photoperiod. Pineal has no influence on ovarian activity during the prespawning and spawning periods of the reproductive cycle. In the late postspawning period, ovarian recrudescence is accelerated after pinealectomy in catfish maintained under short photoperiod (LD 9:15 at 25 degrees C). But under long photoperiod (LD 14:10 at 25 degrees C), pinealectomy delayed ovarian recrudescence. An investigation into the role of the eyes revealed that eye enucleation nullifies the inhibitory effects of LD 9:15 and represses the stimulatory effects of LD 14:10. Combined surgery inhibited ovarian development under both the regimes. It is significant that pinealectomy and/or blinding neither counteracted nor delayed the postspawning ovarian regression. The findings suggest that the role of the pineal in catfish reproduction is variable and depends upon the photoperiod to which they are exposed as well as on the time of the year and the stage of the reproductive cycle. It is concluded that extraretinal and extrapineal photoreceptors also are involved in influencing seasonal reproduction. Further, no effects of melatonin treatment on ovarian activity or on vitellogenin levels during the preparatory or prespawning periods were observed, indicating that the pineal effects on gonadal activity in catfish may not be mediated through the secretion of melatonin.
为研究松果体、眼睛及褪黑素处理对鲶鱼（印度胡鲶）卵巢活动的相对重要性，在年度繁殖周期的不同阶段，对接受松果体切除、眼球摘除或两者皆做的鲶鱼进行短光照周期（LD 9:15）或长光照周期（LD 14:10）处理。在准备期，松果体切除在长光照周期下加速了卵巢再发育，但在短光照周期下未观察到松果体切除的影响。在繁殖周期的产卵前和产卵期，松果体对卵巢活动没有影响。在产后晚期，短光照周期（25摄氏度下LD 9:15）饲养的鲶鱼松果体切除后卵巢再发育加速。但在长光照周期（25摄氏度下LD 14:10）下，松果体切除延迟了卵巢再发育。对眼睛作用的研究表明，眼球摘除消除了LD 9:15的抑制作用并抑制了LD 14:10的刺激作用。联合手术在两种光照条件下均抑制了卵巢发育。重要的是，松果体切除和/或致盲既未抵消也未延迟产后卵巢退化。研究结果表明，松果体在鲶鱼繁殖中的作用是可变的，取决于它们所暴露的光照周期以及一年中的时间和繁殖周期的阶段。得出的结论是，视网膜外和松果体外光感受器也参与影响季节性繁殖。此外，在准备期或产卵前期未观察到褪黑素处理对卵巢活动或卵黄蛋白原水平有影响，这表明松果体对鲶鱼性腺活动的影响可能不是通过褪黑素的分泌介导的。
