GHRL Full-Length MS Protein Standard (NP_057446), Labeled with [U- 13C6, 15N4]-L-Arginine and [U- 13C6, 15N2]-L-Lysine, was produced in human 293 cells (HEK293) with fully chemically defined cell culture medium to obtain incorporation efficiency at Creative-Proteomics. This gene encodes ghrelin-obestatin preproprotein, which generates ghrelin and obestatin. Ghrelin is an endogenous ligand for the growth hormone secretagogue receptor and is involved in regulating growth hormone release. Obestatin was initially reported to be an endogenous ligand for the orphan G protein-coupled receptor GPR39 and was involved in satiety and decreased food intake; however, these findings are controversial. Recent reports show that obestatin is involved in inhibiting thirst and anxiety, improving memory, regulating sleep, affecting cell proliferation, and increasing the secretion of pancreatic juice enzymes. Alternative promoters and alternative splicing result in multiple transcript variants, some of which encode different protein isoforms and some of which do not encode a protein but may regulate the ghrelin-obestatin preproprotein expression. In addition, antisense transcripts for this gene have been identified and may also function in regulation of the ghrelin-obestatin preproprotein expression.