Hiroyuki Kaiya

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We purified ghrelin from stomach extracts of a teleost fish, the Japanese eel (Anguilla japonica) and found that it contained an amide structure at the C-terminal end. Two molecular forms of ghrelin with 21 amino acids were identified by cDNA and mass spectrometric analyses: eel ghrelin-21, GSS(O-n-octanoyl)FLSPSQRPQGKDKKPP RV-amide and eel ghrelin-21-C10,(More)
Complementary deoxyribonucleic acid (cDNA) encoding goldfish preproghrelin was identified using rapid amplification of the cDNA ends (RACE) and reverse transcription (RT)-polymerase chain reaction (PCR). The 490 bp cDNA encodes a 103 amino acid preproghrelin which has a 26 amino acid signal region, 19 amino acid mature peptide and a 55 amino acid C-terminal(More)
In mammals, ghrelin is a non-amidated peptide hormone, existing in both acylated and non-acylated forms, produced mainly from the X/A or ghrelin cells present in the mucosal layer of the stomach. Ghrelin is a natural ligand of the growth hormone (GH) secretagogue-receptor (GHS-R), and functions primarily as a GH-releasing hormone and an orexigen, as well as(More)
We have identified ghrelin from the stomach of rainbow trout. Four isoforms of ghrelin peptide were isolated: the C-terminal amidated type of rainbow trout ghrelin (rt ghrelin) composed of 24 amino acids (GSSFLSPSQKPQVRQGKGKPPRV-amide) is a basic form; des-VRQ-rt ghrelin, which deleted three amino acids (V13R14Q15) from rt ghrelin; and further two types of(More)
In this study, we report the purification, cDNA cloning, and characterization of the novel growth hormone-releasing peptide, ghrelin, in the chicken (Gallus gallus). Chicken ghrelin is composed of 26 amino acids (GSSFLSPTYKNIQQQKDTRKPTARLH) and possesses 54% sequence identity with human ghrelin. The serine residue at position 3 (Ser(3)) is conserved between(More)
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)
We have identified the amphibian ghrelin from the stomach of the bullfrog. We also examined growth hormone (GH)-releasing activity of this novel peptide in both the rat and bullfrog. The three forms of ghrelin identified, each comprised of 27 or 28 amino acids, possessed 29% sequence identity to the mammalian ghrelins. A unique threonine at amino acid(More)
Ghrelin, an acylated brain and gut peptide, is primarily produced by endocrine cells of the gastric mucosa for secretion into the circulation. The major active form of ghrelin is a 28-amino-acid peptide containing an n-octanoyl modification at serine that is essential for activity. Studies have identified multiple physiological functions for ghrelin,(More)
It is known that, in rats, central and peripheral ghrelin increases food intake mainly through activation of neuropeptide Y (NPY) neurons. In contrast, intracerebroventricular (ICV) injection of ghrelin inhibits food intake in neonatal chicks. We examined the mechanism governing this inhibitory effect in chicks. The ICV injection of ghrelin or(More)
A decade has passed since the peptide hormone ghrelin was first discovered in rat stomach. During this period, ghrelin has been identified not only in other mammals but also in fish, amphibians, reptiles and birds, and its physiological functions have been widely investigated. Avian ghrelin was first identified in chickens in 2002 and to date, the amino(More)