Somatostatin receptor (subtypes 1–5) (SSTR1, SSTR2, SSTR3, SSTR4, SSTR5)

Somatostatin receptors are a family of five G protein-coupled receptors (SSTR1–5), each encoded by a distinct gene and sharing a characteristic seven-transmembrane structure[1][2][4]. They are receptors for the peptide hormone somatostatin and mediate its inhibitory effects on hormone release, neurotransmission, and cell proliferation throughout the body[4][2]. Each subtype has a different tissue distribution, ligand affinity, and signaling profile, and may mediate distinct physiological or pharmacological responses. SSTR2, SSTR3, and SSTR5 are therapeutically significant in neuroendocrine tumors and serve as primary targets for somatostatin analogues such as octreotide and lanreotide[2][3]. Diverse expression patterns of the five subtypes in human tissues enable selective targeting by subtype-specific ligands for treatment and diagnosis of various endocrine and neuroendocrine diseases[2][3].

Other names

SSTR1SSTR2SSTR3SSTR4SSTR5SST1SST2SST3SST4SST5SRIF receptor 1–5 (SRIF = somatotropin release-inhibiting factor)Somatostatin receptor subtype 1–5

Activation of Gi/o-coupled G protein pathways inhibiting adenylyl cyclase activity; Inhibition of calcium entry and secretion in target cells; Activation of phospholipase C and mobilization of intracellular Ca2+ (subtype-dependent); Inhibition of growth hormone, insulin, glucagon, and other hormones in target tissue