Development of a practical means for pheromonal manipulation of reproduction.

本研究旨在为开发利用反刍动物自然分泌的信息素人为调控其生殖内分泌功能的可行措施提供必要的信息。我们关注的是导致“雄性效应”的信息素，这是一种在季节性发情的母羊和母羊中由雄性信息素引起的卵巢再激活现象。作为研究的第一步，建立了特异性的生物测定系统。即，通过记录多单位活动（MUA）来监测有意识去卵巢山羊下丘脑GnRH脉冲发生器活动的电生理表现。通过观察经雌二醇照射并保持在16L8D光周期下的去卵巢山羊的GnRH脉冲发生器活性是否增加，来判断是否存在引物信息素活性。通过这种特定的生物测定，我们能够证明从头部和/或颈部获得的头发或皮肤样本的醚提取物在刺激下丘脑GnRH脉冲发生器方面具有很强的信息素活性。因此，所鉴定的信息素物质也显示在雄性山羊皮脂腺中产生雄激素依赖性，并且这些挥发性信息素的分子量小于400。目前的结果强烈表明，在绵羊和山羊中负责雄性效应的信息素是一种与脂肪酸或类固醇递送物在很大程度上具有相同化学特征的分子。在这项研究中获得的信息似乎对进一步纯化哺乳动物信息素至关重要。

The aim of this study was to collect necessary information for the development of feasible measures of artificially manipulating reproductive endocrine function of domestic ruminants by using their naturally-produced pheromones.We focused on the pheromone (s) responsible for the "male effect", a phenomenon known as the ovarian reactivation induced by male pheromones in seasonally anestrous ewes and does. As the first step of approach, a specific bioassay system was established. Namely, the electrophysiological manifestation of the hypothalamic GnRH pulse generator activity was monitored from conscious ovariectomized goats by recording the multiple unit activity (MUA). The existence of primer pheromone activity was assessed based on the observation whether of not the exposure to tested-material resulted in an acceleration of the GnRH pulse generator activity in ovariectomized goats, which had been primed with estradiol and kept under 16L8D photoperiod.By means of this specific bioassay we were able to show that ether extracts from hair or skin samples obtained from head and/or neck regions possess strong pheromone activity in terms of stimulating the hypothalamic GnRH pulse generator. Thus identified pheromonal substances were also shown to be produced androgen dependently at the sebaceous glands of male goats, and the molecular weight of these volatile pheromones would be less than 400. The present results strongly suggest that pheromone (s) responsible for the male effect in sheep and goats is a molecule which largely shares chemical characteristics with either fatty acids or steroid delivertives. The information obtained in this study appears essential for further purifying mammalian pheromones.