Murata K, Wakabayashi Y, Kitago M, Ohara H, Watanabe H, Tamogami S, Warita Y, Yamagishi K, Ichikawa M, Takeuchi Y, Okamura H, Mori Y
Department of Animal Resource Science, The University of Tokyo, Bunkeyo-ku, Tokyo, Japan.
J Neuroendocrinol. 2009 Mar;21(4):346-50. doi: 10.1111/j.1365-2826.2009.01836.x.
In small ruminants, such as goats and sheep, a primer pheromone produced by males induces an out-of-seasonal ovulation in anoestrous females, a phenomenon known as the male effect. The male effect is unique in that an external chemical stimulus can immediately modulate the activity of the hypothalamic gonadotrophin-releasing hormone (GnRH) pulse generator. We have established a monitoring method of the GnRH pulse generator activity in Shiba goat. Using this method as a sensitive bioassay to assess the male effect pheromone activity, we have shown that the male effect pheromone is synthesised in an androgen-dependent manner in the sebaceous glands or their vicinity in specific body regions in goats. Although chemical identity of the pheromone is yet to be determined, analyses of male goat hair extracts by gas chromatography fractionation suggest that the male effect pheromone is a volatile substance with relatively small molecular weight. From morphological and molecular biological studies in goats, it is suggested that the pheromone molecule is detected by a member of the V1R family located on both the olfactory neurones and the vomeronasal sensory neurones, and the pheromone signal is conveyed to the medial nucleus of amygdala via the main olfactory and vomeronasal pathways and, subsequently, to the hypothalamic GnRH pulse generator to enhance its activity.
在小型反刍动物，如山羊和绵羊中，雄性产生的一种引发性信息素可诱导处于发情间期的雌性动物出现非季节性排卵，这一现象被称为雄性效应。雄性效应的独特之处在于，一种外部化学刺激能够立即调节下丘脑促性腺激素释放激素（GnRH）脉冲发生器的活性。我们已经建立了一种监测柴山羊GnRH脉冲发生器活性的方法。利用该方法作为一种灵敏的生物测定法来评估雄性效应信息素的活性，我们发现雄性效应信息素在山羊特定身体区域的皮脂腺或其附近以雄激素依赖的方式合成。尽管该信息素的化学特性尚未确定，但通过气相色谱分级分离对雄山羊毛发提取物进行分析表明，雄性效应信息素是一种分子量相对较小的挥发性物质。从对山羊的形态学和分子生物学研究来看，推测该信息素分子是由位于嗅觉神经元和犁鼻感觉神经元上的V1R家族成员所检测到的，并且该信息素信号通过主嗅觉和犁鼻途径传递至杏仁核内侧核，随后传递至下丘脑GnRH脉冲发生器以增强其活性。
