Prolactin Secretion in a Teleost Fish: Elucidation of Novel Mechanisms for Rapid Steroid Hormone Action

9810326 Borski研究者研究了类固醇皮质醇快速抑制鱼类催乳素分泌的新机制。 类固醇激素通常通过改变DNA作用于靶组织，这是一个需要数小时或数天发生的基因组过程。 博斯基博士表明，皮质醇在几分钟内就能抑制催乳素的释放。 他假设皮质醇也可能通过非基因组的膜受体相关途径起作用，这些途径通常被描述为快速作用的神经递质和肽激素。 Borski博士将测试这一假设，并定义皮质醇和其他类固醇快速改变细胞功能的生化途径。 在许多鱼类中，催乳素对淡水中的生存至关重要，而皮质醇对海水中的维生素调节至关重要。 快速衰减的淡水激素，催乳素，和刺激海水适应皮质醇可能是必不可少的，让鱼类生存在盐度迅速增加。 相反，压力引起的皮质醇升高可能证明不适应的动物生活在淡水条件下，导致高死亡率的商业价值的鱼类，由于处理和现场运输。 这项工作的完成将促进对神经调节的详细工作的理解，这是一个对生理适应至关重要的古老而普遍的过程，并为损害包括生殖，行为和免疫功能在内的生理过程的“应激激素”效应提供了一个综合模型。

9810326 Borski The investigator addresses novel mechanisms by which a steroid, cortisol, rapidly inhibits prolactin secretion in fish. Steroid hormones typically act on target tissues by altering DNA, a genomic process requiring hours or days to occur. Dr. Borski shows cortisol acts within minutes to inhibit prolactin release. He postulates that cortisol may also act through nongenomic, membrane receptor-associated pathways typically described for rapidly acting neurotransmitter and peptide hormones. Dr. Borski will test this hypothesis and define biochemical pathways by which cortisol and other steroids rapidly alter cell function. In many fish, prolactin is critical to survival in fresh water, while cortisol is central to seawater osmoregulation. Rapid attenuation of a freshwater hormone, prolactin, and stimulation of seawater adaptation by cortisol is likely essential for allowing fish to survive rapid increases in salinity. Conversely, stress-induced elevations in cortisol could prove maladaptive for animals living in fresh water conditions which cause high mortality of commercially valuable finfish due to handling and live transport. Completion of this work will advance understanding of the detailed workings underlying osmoregulation, an ancient and universal process critical to physiological adaptation as well as provide an integrative model for "stress hormone" effects that impair physiological processes including reproduction, behavior, and immune function.