Comment on "Obestatin, a Peptide Encoded by the Ghrelin Gene, Opposes Ghrelin's Effects on Food Intake"

Zhang et al . (Research Articles, 11 November 2005, p. 996) reported that obestatin, a peptide derived from the ghrelinprecursor, activated the orphan G protein–coupled receptorGPR39. However, we found that I125- obestatindoes not bind GPR39 and observed no effects of obestatinon GPR39-transfected cells in various functional assays ( cyclic adenosine monophosphateproduction, calcium mobilization, and GPR39 internalization). Our results indicate that obestatinis not the cognateligand for GPR39.