Somatostatin receptor 1, 3, and 5 (SSTR1/3/5)

Somatostatin receptors 1, 3, and 5 (SSTR1, SSTR3, and SSTR5) are G protein-coupled receptors that mediate the inhibitory actions of the hormone somatostatin across various tissues (UniProt P30872, P32745, P35346). These receptors are primarily involved in the suppression of endocrine and exocrine secretions, including growth hormone, insulin, and glucagon (StatPearls, Somatostatin). SSTR1 and SSTR5 are highly expressed in the pituitary gland and pancreatic islets, playing a pivotal role in metabolic regulation and hormone balance. SSTR3 is distinct for its role in promoting apoptosis and inhibiting the cell cycle, which contributes to the anti-tumorigenic properties of somatostatin analogs (PubMed PMID: 10449911). In clinical pathology, these receptors are frequently overexpressed in neuroendocrine tumors and pituitary adenomas, making them valuable therapeutic targets. Drugs like pasireotide are designed to target these specific subtypes with high affinity, providing a broader therapeutic window for treating acromegaly and Cushing's disease compared to SSTR2-selective agents (PubChem CID 9815041). Activation of these receptors leads to the inhibition of adenylyl cyclase and the modulation of ion channels, effectively reducing intracellular signaling that drives hormone overproduction.

Other names

Somatostatin receptor type 1Somatostatin receptor type 3Somatostatin receptor type 5SSTR1SSTR3SSTR5SS1RSS3RSS5RSRIF-4SRIF-2SRIF-1

Agonism of SSTR1, SSTR3, and SSTR5 leads to the activation of inhibitory G proteins (Gi/o), which subsequently inhibits adenylyl cyclase activity, reduces intracellular cyclic AMP (cAMP) levels, and modulates potassium and calcium channels to suppress hormone release and cellular growth (Journal of Clinical Endocrinology & Metabolism, 2014).