ghrelin

The story

From g(rowth) h(ormone)-rel(easing peptide) + -in (suffix forming names of chemical compounds), influenced by Proto-Indo-European *gʰreh₁- (“to grow”): see the December 1999 quotation.

First known use, by meaning

• from 1999 A peptide hormone, secreted in the stomach when empty, that increases appetite and secretion of growth hormone from the pituitary gland.