Isolation and Characterization of Mammalian Reproductive Pheromones

动物个体间通过嗅觉系统进行的化学信息交流在哺乳动物的领地行为、交配行为和母性行为等生殖行为中起着重要的作用。因此，信息素分子的分离和表征是重要的，这不仅是因为所获得的信息可以容易地应用于提高繁殖效率和解决家畜的繁殖问题，而且还因为分离或合成的信息素可以用作神经科学研究领域中用于研究脑功能之谜的有力工具。本研究建立了一种特异性强、重复性好的哺乳动物生殖信息素生物测定体系，并对该体系的生物学特性进行了初步研究。以下丘脑GnRH脉冲发生器活性的电生理表现为参数，通过使用这种独特的生物测定，我们已经能够证明雄山羊毛或其乙醚提取物的气味加速GnRH脉冲发生器瞬间在卵巢切除山羊处理雌二醇和长日照下。相反，来自去势山羊的毛发气味没有影响，表明雄激素依赖性的信息素的产生和分泌。由于信息素物质的应用可以准确地定时与GnRH脉冲的关系，也可以在实时的基础上评估效果，这个过程将为我们提供机会，以分离哺乳动物信息素。目前正在进一步研究物质的化学特性。

It has been well-known that the chemical communication through the olfactory system between individual animals plays an essential role in various aspects of reproductive behavior in mammals, such as territorial behavior, mating behavior and maternal behavior. Isolation and characterization of pheromone molecules are, therefore, important not only because the obtained information can be readily applied to improving the reproductive efficiency and solving reproductive problems in domestic animals but also because the isolated or synthesized pheromones could be used as potent tools in the research field of neuroscience for studying the mystery of brain functions. Unlike in invertebrate species, however, the research on mammalian pheromones has not yet been advanced much so far mainly due to the lack of appropriate bioassay system to assess the pheromonal activity in higher vertebrates such as mammalian species.In the present study, we have established a novel bioassay system with high specificity and reproducibility for mammalian reproductive pheromones, known as the cause of "male effect" in domestic ruminant, using the electrophysiological manifestation of hypothalamic GnRH pulse generator activity as a parameter. By using this unique bioassay, we have been able to demonstrate that the odor of male goat hair or its ether extract accelerates GnRH pulse generator instantaneously in ovariectomized goats treated with estradiol and kept under longday photoperiod. In contrast, hair odor from castrated goats had no effect indicating the androgen dependent production and secretion of pheromones. Since the application of pheromone substance can be accurately timed in relation to the GnRH pulses and also the effect can be assessed on the real-time basis, this procedure will provide us with opportunity to isolate mammalian pheromones. Further study for the chemical characterization of substance (s) is now ongoing.