Reproductive Cycling in Fundulus Heteroclitus

9306123华氏沼虾雌性在其自然栖息地排卵和产卵，其半月周期与大潮一致，一年中长达8个月；它们也在一年中任何时候在恒定的、可控的实验室条件下以半月周期产卵。循环中雌二醇-17β(E_2)水平的高度升高与每一次产卵事件有关。因此，在这种数量丰富且实验上方便的硬骨鱼中，似乎存在着生殖活动的生物钟，并涉及卵巢循环释放E2。华莱士博士将在几次产卵过程中对异纹夜蛾生殖活动的各个方面进行监测，以了解其生殖循环中的操作因素。这些指标包括血液中的卵黄蛋白原和促性腺激素水平，以及下丘脑中的生物胺水平。如果发现卵黄蛋白原和促性腺激素水平波动，将分别在肝脏和脑垂体中测量相应的mRNA水平。促性腺激素调节早熟卵泡芳香酶活性的方式(E2水平升高的来源)也将与卵泡在周期中不同时间对相关激素做出反应的能力一起讨论。将通过在产卵周期的不同时间给予E2来实验研究E2对周期产卵的影响。还将提供其他药物，以探索下丘脑-垂体-性腺轴的因果关系。最后，将对卵的孵化模式和运动活动进行一系列的观察。这种过程中的半月形模式，如果令人信服地证明，将表明异地镰刀菌有一个由基因决定的生物钟，调节其整体生理。***

9306123 Wallace Fundulus heteroclitus females ovulate and spawn in their natural habitat with a semilunar periodicity coincident with spring tides for up to eight months of the year; they also spawn with a semilunar periodicity under constant, controlled laboratory conditions at any time during the year. Highly elevated levels of circulating estradiol-17 Beta (E2)are associated with each spawning episode. A biological clock for reproductive activity, and involving cyclic E2-release by the ovary, thus appears to exist in this abundant and experimentally convenient teleost. In order to appreciate the operant factors in the reproductive cycling of F. heteroclitus, various aspects of reproductive activity will be monitored by Dr. Wallace over several spawning episodes. These include vitellogenin and gonadotropin levels in the bloodstream and biogenic amine levels in the hypothalamus. If vitellogenin and gonadotropin levels are found to fluctuate, corresponding mRNA levels will be measured in the liver and pituitary, respectively. The manner by which gonadotropins regulate aromatase activity in prematurational follicles (the source of elevated E2 levels) will also be addressed together with the competence of follicles to respond to relevant hormones at various times during the cycle. The effect of E2 on cyclic spawning will be experimentally investigated by administering E2 at various times during the spawning cycle. Other drugs will also be provided in order to explore cause and effect relationships in the hypothalamic- pituitary-gonadal axis. Finally, a series of observations will be made on egg hatching patterns and locomotor activity. Semilunar patterns in such processes, if convincingly demonstrated, would indicate that F. heteroclitus has a genetically determined, biological clock that regulates its overall physiology. ***