RESUMEN
Phoenixin (Pnx) is an endogenous peptide known to be involved in reproduction and food intake in rats, with two active isoforms, phoenixin-14 (Pnx-14) and phoenixin-20 (Pnx-20). However, little is known about the functions of Pnx in teleost. Here, pnx was cloned and was detected in all tissues of both male and female in spotted scat (Scatophagus argus), including growth axis, hypothalamus, pituitary, and liver. Real-time PCR analysis showed that pnx in the hypothalamus increased significantly after 2â¯d and 7â¯d fasting, while reduced significantly after re-feeding (Pâ¯<â¯0.05). When pituitary and liver fragments were cultured in vitro with Pnx-14 and Pnx-20 (10â¯nM and 100â¯nM) for 6â¯h, the expression of ghrhr (growth hormone-releasing hormone receptor) and gh (growth hormone) in the pituitary, and ghr1 (growth hormone receptor 1) in the liver increased significantly, except ghr2 (growth hormone receptor 2) incubated with 10â¯nM and 100â¯nM Pnx-20 and ghr1 incubated with 10â¯nM Pnx-20. Similarly, the expression of ghrhr and gh in the pituitary, as well as ghr1 and ghr2 in the liver, increased significantly after injecting S. argus with Pnx-14 and Pnx-20 (10â¯ng/g and 100â¯ng/g body weight). These results indicate that Pnx is likely to be involved in the regulation of food intake, and also regulates the growth of S. argus by increasing ghrhr and gh expression in the pituitary, ghr1 and ghr2 in the liver, and ghr1 directly in the liver.
Asunto(s)
Ingestión de Energía , Proteínas de Peces/metabolismo , Regulación del Desarrollo de la Expresión Génica , Hormonas Hipotalámicas/metabolismo , Hipotálamo/metabolismo , Hormonas Peptídicas/metabolismo , Perciformes/fisiología , Animales , Acuicultura , China , Ingestión de Energía/efectos de los fármacos , Femenino , Proteínas de Peces/administración & dosificación , Proteínas de Peces/genética , Proteínas de Peces/farmacología , Regulación del Desarrollo de la Expresión Génica/efectos de los fármacos , Hormona del Crecimiento/agonistas , Hormona del Crecimiento/genética , Hormona del Crecimiento/metabolismo , Hormonas Hipotalámicas/administración & dosificación , Hormonas Hipotalámicas/genética , Hormonas Hipotalámicas/farmacología , Hipotálamo/efectos de los fármacos , Inyecciones Intraperitoneales , Hígado/efectos de los fármacos , Hígado/metabolismo , Masculino , Especificidad de Órganos , Hormonas Peptídicas/administración & dosificación , Hormonas Peptídicas/genética , Hormonas Peptídicas/farmacología , Perciformes/crecimiento & desarrollo , Hipófisis/efectos de los fármacos , Hipófisis/metabolismo , Isoformas de Proteínas/administración & dosificación , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , Isoformas de Proteínas/farmacología , Distribución Aleatoria , Receptores de Neuropéptido/agonistas , Receptores de Neuropéptido/genética , Receptores de Neuropéptido/metabolismo , Receptores de Hormona Reguladora de Hormona Hipofisaria/agonistas , Receptores de Hormona Reguladora de Hormona Hipofisaria/genética , Receptores de Hormona Reguladora de Hormona Hipofisaria/metabolismo , Receptores de Somatotropina/agonistas , Receptores de Somatotropina/genética , Receptores de Somatotropina/metabolismo , Proteínas Recombinantes/administración & dosificación , Proteínas Recombinantes/metabolismo , Proteínas Recombinantes/farmacología , Técnicas de Cultivo de Tejidos/veterinaria , Aumento de PesoRESUMEN
Spexin (Spx), a novel neuropeptide, composed of 14 amino acid residues, is evolutionally conserved from fish to mammals. It has been suggested that Spx has pleiotropic functions in mammals. However, reports about Spx are very limited. To clarify the roles of Spx in the regulation of reproduction and food-intake in the spotted scat, the spx (ssspx) gene was cloned and analyzed. Analysis of the tissue distribution by RT-PCR showed that ssspx expression was widespread. During ovary development, expression of ssspx was found to be highest in phase II, moderate in phase III, and at its lowest level in phase IV. Ssspx expression was significantly down-regulated in the hypothalamus after treatment with E2 both in vitro and in vivo. A significant increase of ssspx was observed after 2 and 7â¯days of food deprivation. However, the ssspx transcript levels in the 7â¯day fasting group decreased significantly after refeeding 3â¯h after the scheduled feeding time. This suggests that ssSpx may be involved in the regulation of reproduction and food-intake in the spotted scat.