Kisspeptin has an indispensable role in gonadotropin-releasing hormone/gonadotropin secretion in mammals. In rodents, kisspeptin neurons are located in distinct brain regions, namely the anteroventral periventricular nucleus-periventricular nucleus continuum (AVPV/PeN), arcuate nucleus (ARC), and medial amygdala (MeA). Among them, the physiological role of AVPV/PeN kisspeptin neurons in males has not been clarified yet. The present study aims to investigate the acute effects of the olfactory and/or mating stimulus with a female rat on hypothalamic and MeA Kiss1 mRNA expression, plasma luteinizing hormone (LH) and testosterone levels in male rats. Intact male rats were exposed to the following stimuli: exposure to clean bedding; exposure to female-soiled bedding as a female-olfactory stimulus; exposure to female-soiled bedding and mating stimulus with a female rat. The mating stimulus significantly increased the number of the AVPV/PeN Kiss1 mRNA-expressing cells in males within 5 minutes after the exposure, and significantly increased LH and testosterone levels, followed by an increase in male sexual behavior. Whereas, the males exposed to female-soiled bedding showed a moderate increase in LH levels and no significant change in testosterone levels and the number of the AVPV/PeN Kiss1 mRNA-expressing cells. Importantly, none of the stimuli affected the number of Kiss1 mRNA-expressing cells in the ARC and MeA. These results suggest that the mating-induced increase in AVPV/PeN Kiss1 mRNA expression may be, at least partly, involved in stimulating LH and testosterone release, and might consequently ensure male mating behavior. This study would be the first report suggesting that the AVPV/PeN kisspeptin neurons in males may play a physiological role in ensuring male reproductive performance.

中文翻译：

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在雄性大鼠 LH 和睾酮释放增加之前，交配诱导的前腹侧室周核Kiss1 mRNA 表达增加

Kisspeptin 在哺乳动物的促性腺激素释放激素/促性腺激素分泌中具有不可或缺的作用。在啮齿类动物中，kisspeptin 神经元位于不同的大脑区域，即前腹侧室周核-室周核连续体 (AVPV/PeN)、弓状核 (ARC) 和内侧杏仁核 (MeA)。其中，AVPV/PeN Kisspeptin 神经元在雄性中的生理作用尚未阐明。本研究旨在研究雌性大鼠的嗅觉和/或交配刺激对雄性大鼠下丘脑和 MeA Kiss1 mRNA 表达、血浆促黄体激素 (LH) 和睾酮水平的急性影响。完整的雄性大鼠暴露于以下刺激：暴露于干净的床上用品；暴露于女性弄脏的床上用品作为女性嗅觉刺激；暴露于雌性弄脏的床上用品和与雌性大鼠交配的刺激。交配刺激在暴露后 5 分钟内显着增加了雄性中表达 AVPV/PeN Kiss1 mRNA 的细胞数量，并显着增加了 LH 和睾酮水平，随后雄性性行为增加。然而，暴露于女性弄脏的床上用品的雄性表现出 LH 水平的适度增加，而睾酮水平和 AVPV/PeN Kiss1 mRNA 表达细胞的数量没有显着变化。重要的是，没有一种刺激影响 ARC 和 MeA 中 Kiss1 mRNA 表达细胞的数量。这些结果表明，交配诱导的 AVPV/PeN Kiss1 mRNA 表达增加可能，至少部分地，参与刺激 LH 和睾酮释放，并因此可能确保雄性交配行为。