RESUMO
The present study aimed to determine the relationship between melatonin and gonadotropin-inhibitory hormone (GnIH) and their effect on reproduction in cinnamon clownfish, Amphiprion melanopus. Accordingly, we investigated the expression pattern of GnIH, GnIH receptor (GnIH-R), and melatonin receptor (MT-R1) mRNA and protein, as well as the plasma levels of melatonin, during sex change in cinnamon clownfish. We found that GnIH and MT-R1 mRNA and melatonin activity were higher in fish with mature brain than in fish with developing gonads, and using double immunofluorescence staining, we found that both GnIH and MT-R1 proteins were co-expressed in the hypothalamus of cinnamon clownfish. These findings support the hypothesis that melatonin plays an important role in the negative regulation of maturation and GnIH regulation during reproduction.
Assuntos
Proteínas de Peixes/metabolismo , Hormônios Hipotalâmicos/metabolismo , Melatonina/metabolismo , Perciformes/crescimento & desenvolvimento , Receptores de Melatonina/metabolismo , Comportamento Sexual Animal , Animais , Feminino , Proteínas de Peixes/análise , Proteínas de Peixes/genética , Regulação da Expressão Gênica no Desenvolvimento , Hormônios Hipotalâmicos/análise , Hormônios Hipotalâmicos/genética , Hipotálamo/crescimento & desenvolvimento , Hipotálamo/metabolismo , Masculino , Melatonina/análise , Melatonina/sangue , Melatonina/genética , Perciformes/sangue , Perciformes/metabolismo , RNA Mensageiro/genética , Receptores de Melatonina/análise , Receptores de Melatonina/genética , Desenvolvimento SexualRESUMO
Melatonin (N-acetyl-5-methoxy-tryptamine), a principal product of the pineal gland, is produced mainly during the dark phase of the circadian cycle. This hormone plays a crucial role in the regulation of circadian and seasonal changes in various aspects of physiology and neuroendocrine functions. In mammals, melatonin can influence sexual maturation and reproductive functions via activation of its receptors and binding sites in the hypothalamic-pituitary-gonadal (HPG) axis. This review summarizes current knowledge of melatonin on the hypothalamus, pituitary gland, and gonads. We also review recent progress in clinical applications of melatonin or potentials of using melatonin, as a reducer of oxidative stress, to improve reproductive functions for the diseases such as women infertility.