Mating-induced increase in Kiss1 mRNA expression in the anteroventral periventricular nucleus prior to an increase in LH and testosterone release in male rats.

Youki Watanabe
Kana Ikegami
Sho Nakamura
Yoshihisa Uenoyama
Hitoshi Ozawa
Kei-Ichiro Maeda
Hiroko Tsukamura
Naoko Inoue

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.

The Journal of reproduction and development

66

6

10.1262/jrd.2020-067

https://doi.org/10.1262/jrd.2020-067
https://www.ncbi.nlm.nih.gov/pubmed/32968033
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7768167