創薬とペプチド

抄録

A complex network of cell-cell communication system by peptide hormones works for maintaining the mammalian homeostatic balance. For further understanding the intricate mechanisms of the regulation, it is important to discover unidentified bioactive peptides. By using our own methods, we have been searching for peptides which may be relevant to circulation control. In the course of these studies, we discovered 3 natriuretic peptides, ANP (1984), BNP (1988) and CNP (1990), and also adrenomedullin (1993). These studies elucidated new regulatory mechanisms of cardiovascular system, and also brought their therapeutic potential on cardiovascular diseases. In 1999, we discovered ghrelin, a novel growth hormone (GH)-releasing peptide as an endogenous ligand for GHS-R, from rat stomach. Ghrelin was a 28-amino acid peptide with a marvelous structure, in which the Ser-3 residue was n-octanoylated. This n-octanoyl modification was essential for the activity. Ghrelin is primarily produced in distinct endocrine cells in the stomach. Ghrelin-producing neurons are also present in the hypothalamic arcuate nucleus, a region that regulates GH release and food intake. In fact, ghrelin stimulates GH release and feeding when administered centrally or peripherally. Beside these effects, ghrelin is also involved in the regulation of cardiovascular system. In the clinical trial, 3-week administration of ghrelin improved left ventricular structure and function, exercise capacity, and muscle wasting in patients with chronic heart failure (CHF). The occurrence of ghrelin in both stomach and hypothalamus will give a new dimension to the regulation of GH release and feeding. Further, GHS-R is widely expressed in peripheral tissues. Ghrelin also thus has multifaceted roles in the cardiovascular and metabolism systems. In my presentation, I will discuss about therapeutic potential of endogenous bioactive peptides.