Somatostatin-28 (1-14) is an N-terminal fragment of the neuropeptide somatostatin-28, which originates from the posttranslational cleavage of prosomatostatin, derived from the larger precursor preprosomatostatin.
Somatostatin, also known as growth hormone-inhibiting hormone, is a naturally-occurring peptide hormone of 14 or 28 amino acid residues that regulates the endocrine system. It is secreted by the D cells of the islets to inhibit the release of insulin and
Cortistatin-14 is a neuropeptide have structural similarity to somatostatin-14. It is produced in the cortex and hippocampus of central nervous system.
Cortistatin-29 is a neuropeptide that is structurally similar to somatostatin-28. It is produced by cleavage of preprocortistatin to procortistatin, which is cleaved at dibasic amino acids to form cortistatin-29 and cortistatin-14 as well as other partial cleavage products. Cortistatin mRNA is expressed in the human brain and in interneurons of the rat hippocampus and cerebral cortex. Cortistatin-29 binds to somatostatin (SST) receptors with IC50 values of 2.8, 7.1, 0.2, 3, and 13.7 nM for SST1-5, respectively. Cortistatin-29 is found at similar levels as cortistatin-14 in mouse AtT20 cells but is secreted at a lower level. Cortistatin-29 corresponds to residues 85-112 of the rat peptide sequence.