Ghrelin and ghrelin receptor (GHSR) in Chinese alligator, alligator sinensis: Molecular characterization, tissue distribution and mRNA expression changes during the active and hibernating periods

•We described the molecular structure of ghrelin and GHSR in the Chinese alligator.•Ghrelin and GHSR sequences share high identity with American alligator and birds.•The active core of ghrelin and binding site of GHSR were similar to those of mammals.•Ghrelin and GHSR were highly expressed in central and multiple peripheral tissues.•Ghrelin and GHSR were increased in brain but decreased in multiple peripheral tissues.