An anorexic peptide encoded by the preproghrelin gene
Multifunctional peptide, ghrelin [ code 4372-s and 4373-s], was discovered by Kojima et al. in 1999, and its precursor sequence was also clarified in the same report [Nature, 402, 656 (1999)]. Most recently, a group at Stanford University School of Medicine has found a novel peptide named “obestatin” by using a bioinformatic prediction method they developed to analyze preproghrelin [Science, 310, 996 (2005)]. This group has also identified novel peptides such as stresscopin/stresscopin-related peptide [ code 4387-s and code 4388-s] and intermedin [also called adrenomedullin 2, code 4421-s and 4422-s] by using the same method.
Obestatin was predicted to be a 23-residue peptide with carboxyl-terminal amide functionality, which is flanked by mono basic residues in the preproghrelin sequence in the form of a Gly-extended structure. Endogenous obestatin was then isolated from rat stomach extracts, by which their prediction was confirmed to be correct. The carboxyl-terminal 13-residue peptide of obestatin was also isolated as a minor component. Obestatin is conserved in the preproghrelin sequences of 11 different mammalian species, including human. Furthermore, the orphan G-protein-coupled receptor, GPR39, was identified to be a receptor of obestatin. Obestatin is a novel biologically active peptide that is identified by applying the modern technique in the post-genome era.
Synthetic obestatin suppressed food intake in mice: it is effective at doses of 1 micro mol/kg after intraperitoneal injection and 8 nmol/kg after intracerebroventricular injection. This is very interesting because this effect is opposed to that of ghrelin. Obestatin also exerts the opposite effects to the role of ghrelin in the gastric emptying activity as well as the contractile activity in the jejunum. Thus, in contrast to ghrelin, obestatin may be an anorexic peptide leading to body weight loss. Therefore, obestatin will be a fascinating peptide to clarify the mechanism of obesity in humans because obestatin and counteracting ghrelin are encoded in the same gene and may be expressed simultaneously in the body.
|4429-s||Obestatin (Human)||Food Intake Suppressor / Ligand for GPR39||0.1 mg vial||¥8,000|
|4430-s||Obestatin (Rat, Mouse)||Food Intake Suppressor / Ligand for GPR39||0.1 mg vial||¥8,000|
|4372-s||Ghrelin (Human)||Endogenous Growth-Hormone Releasing Peptide with Novel Regulatory Mechanism||0.1 mg vial||¥20,000|
|4373-s||Ghrelin (Rat)||Endogenous Growth-Hormone Releasing Peptide with Novel Regulatory Mechanism||0.1 mg vial||¥20,000|