Effects of gonadotropin inhibitory hormone or gonadotropin-releasing hormone on reproduction-related genes in the protandrous cinnamon clownfish, Amphiprion melanopus.
Hypothalamic peptide neurohormones such as gonadotropin-releasing hormones (GnRHs) and gonadotropin-inhibitory hormone (GnIH) play pivotal roles in the control of reproduction and gonadal maturation in teleost fish. To study the effects of GnIH on fish reproduction, we investigated the influence of seabream GnRH (sbGnRH) and GnIH (both alone and in combination) on levels of reproductive genes (GnIH, GnIH-receptor [GnIH-R], melatonin receptor [MT3], sbGnRH, and gonadotropic hormones [GTHs]) during different stages of gonadal maturation in male, female, and immature cinnamon clownfish, Amphiprion melanopus. The results showed that the expression levels of GnIH, GnIH-R, and MT3 genes increased after the GnIH injection, but decreased after the sbGnRH injection. In addition, these gene expression levels gradually lowered after GnIH3 and sbGnRH combination treatment, as compared to the MT3 mRNA levels of GnIH treatment alone. However, the expression levels of the HPG (hypothalamus-pituitary-gonad) axis genes (sbGnRH and GTHs) decreased after the GnIH injection, but increased after the sbGnRH injection. In all cinnamon clownfish groups, HPG axis gene mRNA levels gradually decreased after mixed GnIH3 and sbGnRH treatment, compared to GnIH treatment alone. The present study provides novel information on the effects of GnIH and strongly supports the hypothesis that GnIH plays an important role in the negative regulation of the HPG axis in the protandrous cinnamon clownfish.
Division of Marine BioScience, Korea Maritime and Ocean University, Busan 49112, Republic of Korea.
Young Jae
YJ
Choi
Division of Marine BioScience, Korea Maritime and Ocean University, Busan 49112, Republic of Korea.
Na Na
NN
Kim
Department of Biological Sciences, University of Calgary, 2500 University Drive N.W. Calgary, Alberta T3B 2V4, Canada.
Hamid R
HR
Habibi
Division of Marine BioScience, Korea Maritime and Ocean University, Busan 49112, Republic of Korea. Electronic address: choic@kmou.ac.kr.
Cheol Young
CY
Choi
D000818:Animals; D005260:Female; D005399:Fishes / Q000235:genetics* / Q000378:metabolism; D007987:Gonadotropin-Releasing Hormone / Q000378:metabolism*; D008297:Male; D008550:Melatonin / Q000378:metabolism*; D012741:Sexual Maturation
D007987:Gonadotropin-Releasing Hormone; D008550:Melatonin
Cinnamon clownfish; Gonadotropin inhibitory hormone; Hypothalamus–pituitary–gonad axis; Melatonin; Seabream gonadotropin-releasing hormones; Sex maturation