Somatostatin

Somatostatin (also known as growth hormone-inhibiting hormone (GHIH) or somatotropin release-inhibiting factor (SRIF)) or somatotropin release-inhibiting hormone is a peptide hormone that regulates the endocrine system and affects neurotransmission and cell proliferation via interaction with G-protein-coupled somatostatin receptors and inhibition of the release of numerous secondary hormones.

Somatostatin has two active forms produced by alternative cleavage of a single preproprotein: one of 14 amino acids, the other of 28 amino acids.

In all vertebrates, there exists six different somatostatin genes that have been named SS1, SS2, SS3, SS4, SS5, and SS6. The six different genes along with the five different somatostatin receptors allows somatostatin to possess a large range of functions. Humans have only one somatostatin gene, SST.