ghrel·in 
(grĕlən)
(grĕlən)n.
A hormone that is secreted by cells in the stomach and promotes hunger before an expected meal, decreases in amount after eating, and promotes secretion of growth hormone.
[Coined by its discoverers from ghrē-, reconstructed Proto-Indo-European root of English grow; see GROW + -IN (probably influenced by g(rowth)-h(ormone)-rel(easing peptide), a description of ghrelin's function and chemical composition).]