[Somatostatin and its receptors].

Somatostatin-14 and somatostatin-28 are derived from the same peptide, prosomatostatin by the post-translational modification and make a somatostatin family. Recent advance in molecular biology has revealed that somatostatin receptors also constitute a family of structurally-related proteins. The members of the somatostatin receptor family are SSTR1-5, which have different expression pattern, pharmacological characterization and coupling with intracellular second messenger systems. Efficacy of SMS 201-995, a clinically available somatostatin analog, against endocrine tumors seems to be correlated with expression of SSTR2 which has a high affinity for SMS 201-995. Cloning of somatostatin receptors will further facilitate development and application of somatostatin analogs in diagnosis and treatment of tumors.