Somatostatin, also known as growth hormone-inhibiting hormone (GHIH), is a peptide hormone that regulates the endocrine system and influences neurotransmission and cell proliferation through interaction with G protein-coupled somatostatin receptors. It inhibits the release of numerous secondary hormones.
Somatostatin has two active forms produced by alternative cleavage of a single preproprotein: one consisting of 14 amino acids (shown to the right in the infobox), and another shorter form with only 28 amino acids, which includes an additional 14 amino acids at one end.