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Ghrelin is a novel growth hormone (GH)-releasing peptide,which has been identified as an endogenous ligand for GH-secretagogue receptor.The sequence of ghrelin has been determined in many species from fish to mammals.In this study,to reveal the production and characteristic of ghrelin in the reindeer (Rangifer tarandus),the full-length cDNA encoding ghrelin were cloned from reindeer stomach using reverse transcription PCR(RT-PCR) and rapid amplification of complementary deoxyribonucleic acid ends (RACE).Results of cDNA cloning and sequence analysis revealed that the full-length of reindeer ghrelin cDNA was composed of 604 bases that included a 5′-untranslated region (57 bp),an open reading frame (ORF) (405 bp) encoding a prepro-ghrelin of 134 amino acids,and a 3′-untranslated region (142 bp).The predicted prepro-ghrelin of 134 amino acids included N-terminal signal peptide of 41 amino acids that was longer than any other animals ghrelin,the predicted mature ghrelin peptide of 27 amino acids which showed high homology to goat (100%),sheep (100%) and cattle (96.3%) mature ghrelin peptide,and C-terminal peptide of 66 amino acids.Thus,the present study indicates a structural divergence of peptide length in reindeer ghrelin.In conclusion,we have identified a noval ghrelin from reindeer,and found that it is highly conserved with other ruminants ghrelin sequences.