Somatostatin receptor subtype 2 and subtype 5 (SSTR2 and SSTR5)

Somatostatin receptor subtype 2 and subtype 5 (SSTR2 and SSTR5) are members of the G protein-coupled receptor (GPCR) family that primarily mediate the inhibitory effects of the peptide hormone somatostatin on hormone secretion, cellular proliferation, and neurotransmission[3][4][5]. Both receptors share the canonical seven-transmembrane domain structure of class A GPCRs and function mainly via Gi/o protein signaling, leading to inhibition of adenylyl cyclase and downstream reductions in cyclic AMP levels[3][4][5][7]. They are highly expressed in neuroendocrine tissues, including pancreas, pituitary, and numerous tumor types—most notably neuroendocrine tumors, where their overexpression drives both diagnostic imaging (via radiolabeled somatostatin analogues) and targeted therapies (e.g., octreotide and lanreotide)[3][4][5][7]. Structural and mutational studies have revealed the molecular basis for subtype-selectivity and ligand recognition, critical for rational drug design[1][2][7]. SSTR2 and SSTR5 have distinct and overlapping tissue distributions and signaling roles and are essential targets in the management of hormone-secreting tumors, acromegaly, and related endocrine and oncologic diseases[5][6][8].

Other names

SSTR2SSTR5Somatostatin receptor type 2Somatostatin receptor type 5sst2sst5SRIF receptor subtype 2SRIF receptor subtype 5

Agonists bind SSTR2 or SSTR5, activating inhibitory G-proteins (Gi/o) Inhibits adenylyl cyclase, reduces cAMP production Inhibits voltage-gated calcium channels and reduces hormone secretion Suppresses cell proliferation, stimulates apoptosis in tumor cells