Novel insights into somatostatin receptor physiology

The experimental data reviewed in the present paper deal with the molecular events underlying the
agonist-dependent regulation of the distinct somatostatin receptor subtypes and may suggest
important clues about the clinical use of somatostatin analogs with different pattern of receptor
specificity for the in vivo targeting of tumoral somatostatin receptors. Somatostatin receptor subtypes
are characterized by differential b-arrestin trafficking and endosomal sorting upon agonist binding
due, at least in part, to the differences in their C-terminal tails. Moreover, the subcellular expression
pattern of somatostatin receptor subtypes and their activity in response to agonist treatment are
affected by intracellular complements, such as proteins involved in intracellular vesicle trafficking.
Different somatostatin analogs may induce distinct conformations of the receptor/ligand complex,
preferentially coupled to either receptor signaling or receptor endocytosis.