Involvement of the kisspeptin system in regulation of sexual behaviors in medaka

Mikoto Nakajo; Shinji Kanda; Yoshitaka Oka

doi:10.1016/j.isci.2024.108971

Involvement of the kisspeptin system in regulation of sexual behaviors in medaka

iScience. 2024 Jan 19;27(2):108971. doi: 10.1016/j.isci.2024.108971. eCollection 2024 Feb 16.

Authors

Mikoto Nakajo¹, Shinji Kanda², Yoshitaka Oka³

Affiliations

¹ Department of Physiology, Division of Life Sciences, Faculty of Medicine, Osaka Medical and Pharmaceutical University, Takatsuki, Osaka, Japan.
² Laboratory of Physiology, Atmosphere and Ocean Research Institute, The University of Tokyo, Kashiwa, Chiba, Japan.
³ Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Bunkyo, Tokyo, Japan.

Abstract

In mammals, kisspeptin (Kiss1) neurons are generally considered as a sex steroid-dependent key regulator of hypothalamic-pituitary-gonadal (HPG) axis. In contrast, previous studies in non-mammalian species, especially in teleosts, propose that Kiss1 is not directly involved in the HPG axis regulation, which suggests some sex-steroid-dependent functions of kisspeptin(s) other than the HPG axis regulation in non-mammals. Here, we used knockout (KO) medaka of kisspeptin receptor-coding genes (gpr54-1 and gpr54-2) and examined possible roles of kisspeptin in the regulation of sexual behaviors. We found that the KO pairs of gpr54-1, but not gpr54-2, spawned fewer eggs and exhibited delayed spawning than wild type pairs. Detailed behavior analysis suggested that the KO females are responsible for the delayed spawning and that the KO males showed hyper-motivation for courtship. Taken together, the present finding suggests that one of the reproductive-state-dependent functions of the Kiss1 may be the control of successful sexual behaviors.

Keywords: Biological sciences; Developmental biology; Molecular biology; Molecular mechanism of behavior.