Determination of nonmammalian ghrelin.

Ghrelin is a peptide with a unique molecular modification by a fatty acid such as n-octanoic acid. The acyl modification is necessary for ghrelin to bind to its receptor (growth hormone secretagogue-receptor 1a, GHS-R1a) and to induce subsequent intracellular Ca(2+) signaling. Ghrelin is widely expressed in mammals as well as in nonmammalian vertebrates. In our laboratory, a method for efficient purification of ghrelin from a small amount of tissues has been established. Here, we introduce the identification process of ghrelin in nonmammalian vertebrates.