Drug design at peptide receptors: Somatostatin receptor ligands

Abstract

Somatostatin (SRIF, somatotropin release inhibiting factor), discovered for its inhibitory action on growth hormone (GH) secretion from pituitary, is an abundant neuropeptide. Two forms, SRIF14 and SRIF28 exist. Recently, a second family of peptides with very similar sequences and features was described; the cortistatins (CST), CST17 and CST29 which are brain selective. The five cloned SRIF receptors (sst1-5) belong to the G-protein coupled/heptathelical receptor family. Structural and operational features distinguish two classes of receptors; SRIF1 sst2/sst3/sst5 (high affinity for octreotide or seglitide) and SRIF2 = sst1/sst4 (very low affinity for the aforementioned ligands). The affinit..