Time-related effects of various LED light spectra on reproductive hormones in the brain of the goldfish Carassius auratus

In this study, we examined differences among the gonadotropin-inhibitory hormone (GnIH), kisspeptin 1 (Kiss1), Kiss 1 receptor (G-protein-coupled receptor 54; GPR54), melatonin receptor 1 (MT1), and melatonin levels in brain cells of goldfish Carassius auratus exposed to white fluorescent light and three light-emitting diode (LED) wavelength and melatonin treatments in the culture medium. In the green and blue LED treatment groups, GnIH and MT1 mRNA expression levels were significantly lower than in the other groups; conversely, levels significantly increased in the melatonin treatment groups. Additionally, expression levels of Kiss1 and its receptor, GPR54, in the white fluorescent and red LED light groups were significantly lower than the other groups, but levels also significantly decreased in the melatonin treatment groups. These results suggest that white fluorescent and red wavelengths downregulate the production of neurohormones in the brains of C. auratus and thus may inhibit sexual maturation in goldfish.