Ghrelin is an appetite-stimulatory signal from stomach with structural resemblance to motilin. - Asakawa,A.; Inui,A.; Kaga,T.; Yuzuriha,H.; Nagata,T.; Ueno,N.; Makino,S.; Fujimiya,M.; Niijima,A.; Fujino,M.A.; Kasuga,M. (Gastroenterology, 2001)