Puberty regulation in chub mackerel Scomber japonicus, an important aquaculture fish species, via reproductive endocrine mechanism

Abstract

The vertebrate reproductive system is controlled by the brain–pituitary–gonadal reproductive endocrine axis (BPG axis). Gonadotropin-releasing hormone (GnRH) secreted from the hypothalamus regulates the secretion of two gonadotropic hormones (GTHs), follicle-stimulating hormone (FSH) and luteinizing hormone (LH), in the pituitary gland. Steroid hormones, such as androgens and estrogens, secreted in response to GTH stimulation, regulate the development of male and female gametes. Recently, various neuropeptides have been identified in mammals as factors that regulate the BPG axis from the upstream, demonstrating their importance. The author’s main research theme is “Understanding the mechanism underlying puberty control in aquaculturally important species.” They have been actively investigating the regulatory mechanism of the BPG axis in the puberty of chub mackerel Scomber japonicus, an important fishery species. With this species, researchers can systematically collect target organs, cells, and other organs from individuals at each developmental stage, from fertilized eggs to adult fish after spawning. A highly reproducible rearing experimental system has been established, enabling verification of the knowledge gained through feedback to reared individuals. Furthermore, it has recently become possible to quickly and efficiently produce gene knockout lines using genome editing. This article introduces the mechanism of puberty control in chub mackerel by fully leveraging this experimental platform. Focus will be directed to the functions of kisspeptin, which triggers puberty by regulating GnRH secretion in mammals, and leptin, which transmits nutritional information to the reproductive axis.