Materials and Methods

Monitoring leptin activity using the chicken leptin receptor ar ter, Rah ity o i.hu species (about 60 and 38 % identical amino acids between activation profiles were observed with cells transfected with 2000) demonstrated its syntenic position relative to that of the molecular level is of great interest for both agricultural and originating from both humans and frogs activate CLEPR with prepared as described previously (Crespi & Denver 2006). 325Journal of Endocrinology (2008) 197, 325–333 DOI: 10.1677/JOE-08-0065human LEPR. In general, the tissue-specific pattern of expression of the chicken and turkey LEPRs parallels that of mammalian LEPRs, with some variations (Horev et al. 2000, Ohkubo et al. 2000, Richards & Poch 2003). The recent cloning of leptin and LEPR genes in Xenopus laevis (Crespi & Denver 2006) and leptin’s demonstrated role in energy balance in frogs show that this signaling pathway is ancient, likely arising very early in the evolution of vertebrates. In chickens, understanding the control of energy balance at the high potency. This bioassay is expected to be valuable for the identification of CLEPR natural ligands, and for further study of this signaling pathway’s role in avian growth and physiology