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We have identified ghrelin and cDNA encoding precursor protein from the stomach of a euryhaline tilapia, Oreochromis mossambicus. The sequence of 20-amino acid tilapia ghrelin is GSSFLSPSQKPQNKVKSSRI. The third serine residue was modified by n-decanoic acid. The carboxyl-terminal end of the peptide possessed an amide structure. RT-PCR analysis revealed high(More)
Recently, a new peptide, ghrelin, which specifically stimulates growth hormone (GH) release from the pituitary, was identified in the rat and human stomach. Ghrelin has been shown to stimulate GH release by acting through a growth hormone secretagogue receptor. We have identified two ghrelins (ghrelin-C8 and -C10) in the stomach of tilapia, a euryhaline(More)
Two PRL-releasing peptides (PrRP20 and PrRP31) were recently identified from mammalian hypothalamus by an orphan receptor strategy, and a C-terminal RF (arginyl-phenylalamyl-) amide peptide (RFa), structurally related to mammalian PrRP, was also identified from the brain of the Japanese crucian carp (C-RFa) by an intestine-contracting assay. However, to(More)
This study assessed the endocrine and ionoregulatory responses by tilapia (Oreochromis mossambicus) to disturbances of hydromineral balance during confinement and handling. In fresh water (FW), confinement and handling for 0.5, 1, 2 and 6h produced elevations in plasma cortisol and glucose; a reduction in plasma osmolality was observed at 6h. Elevations in(More)
Recently, ghrelin (Ghr), a new peptide which specifically stimulates growth hormone (GH) release from the pituitary, was identified in the rat and human stomach. Ghrelin has been shown to stimulate GH release by acting through a growth hormone secretagogue (GHS) receptor in the rat. The present study describes the in vitro effect of rat Ghr on the release(More)
The effects of prolonged nutrient restriction (fasting) and subsequent restoration (re-feeding) on the growth hormone (GH)/insulin-like growth factor (IGF) axis were investigated in the tilapia (Oreochromis mossambicus). Mean weight and specific growth rate declined within 1 week in fasted fish, and remained lower than controls throughout 4 weeks of(More)
Hypophysectomy and hormone replacement therapy were conducted to investigate the regulation of branchial mitochondrion-rich cell (MRC) recruitment and hormone receptor expression in euryhaline tilapia (Oreochromis mossambicus). Gene expression and immunolocalization of Na(+)/Cl(-) cotransporter (NCC) and Na(+)/K(+)/2Cl(-) cotransporter (NKCC) were used as(More)
We investigated in vitro effects of insulin-like growth factors (IGF-I and -II) on growth hormone (GH) and prolactin (PRL) release and gene expression in euryhaline tilapia, Oreochromis mossambicus. Pituitaries were removed from freshwater-acclimated adult males and incubated for 2-24h in the presence of human IGF-I or -II at doses ranging from 1-1000 ng/ml(More)
This study characterized endocrine and ionoregulatory responses accompanying seawater (SW) acclimation in Mozambique tilapia (Oreochromis mossambicus). Changes in plasma hormones and gene expression of hormone receptors, putative osmosensors, and ion transporters in the gill were measured. Transfer of freshwater (FW)-acclimated tilapia to SW resulted in a(More)
Igf1 and Igf2 stimulate growth and development of vertebrates. In mammals, liver-derived endocrine Igf1 mediates the growth promoting effects of GH during postnatal life, whereas Igf2 stimulates placental and fetal growth and is not regulated by GH. Insulin enhances Igf1 production by the mammalian liver directly, and by increasing hepatocyte sensitivity to(More)