Kisspeptin (Kiss) and its cognate receptor, kisspeptin receptor (KissR; G protein coupled receptor 54, GPR54), have recently been recognized as potent regulators of reproduction in teleosts. Additionally, leptin plays an important role in energy homeostasis and reproductive function in teleosts. The purpose of this study was to examine differences in the concentration of the hormones of the Kiss/KissR system and leptin and the expression of their underlying genes, all of which are involved in the sexual maturation of female goldfish, Carassius auratus, following treatment with Kiss. The expression levels of KissR increased after the Kiss injection. Furthermore, the peptide hormone leptin also increased after the injection (in vivo and in vitro). Additionally, the expression of GnRH and GTHs (GTHα, FSHβ, and LHβ) increased in the brain and pituitary (in vitro and in vitro). These results support the hypothesis that Kiss plays important roles in the direct regulation of the hypothalamus-pituitary-gonad axis and leptin in goldfish. Therefore, we suggest that Kiss system gene expression is correlated with energy balance and reproduction.

시각막의 바탕과 줄무늬 색상을 흑색, 청색, 적색, 백색과 황색 중 2가지씩 순열시킨 20가지 경우에 대하여 붕어 Carassius carassius와 금붕어 Carassius auratus의 시각운동반응을 조사한 결과는 다음과 같다. 1. 붕어의 시각운동반응율은 적색-흑색, 청색-황색과 백색-흑색 일 때 80~90%로 높았으며, 황색-백색, 백색-황색, 흑색-청색, 청색-흑색과 적색-백색일 때 25~40%로 낮았다. 2. 금붕어의 시각운동반응율은 백색-황색, 청색-흑색과 백색-적색을 제외하고는 80%이상으로 높았었다. 3. 붕어의 3분 동안의 평균선 회수는 황색-청색, 백색-청색, 황색-흑색과 백색-흑색일 때 7.5~9.5회로 많았으며, 청색-적색, 황색-백색, 흑색-청색, 적색-모든 색과 청색-흑색일 때 1.8~3.9회로 적었다. 4. 금붕어의 3분 동안의 평균선 회수는 황색-청색, 백색-청색과 백색-흑색일 때만 4.1~4.9회이고, 나머지는 1.6~3.5회로 적었다

We investigated the effect of light spectra on circadian rhythm by exogenous prolactin (PRL) by using light emitting diodes (LEDs): red, green, and purple. We injected PRL into live fish or treated cultured brain cells with PRL. We measured changes in the expressions of period 2 (Per2), cryptochrome 1 (Cry1), melatonin receptor 1 (MT1) mRNAs, and MT1 proteins, and in the plasma PRL, serotonin, and melatonin levels. After PRL injection and exposure to green LED light, MT1 expression and plasma melatonin levels were significantly lower, but the expressions of Per2 and Cry1 were significantly higher than others. Plasma serotonin after PRL injection and exposure to red LED light was significantly lower than others. These results indicate that injection of high concentration PRL inhibits melatonin, and inhibited melatonin regulates circadian rhythm via clock genes and serotonin. Thus, exogenous PRL regulates the circadian rhythm and light spectra influence the effect of PRL in goldfish.