A broad inhibitory peptide produced in the brain, pancreas, and gut that suppresses growth hormone, insulin, glucagon, and multiple GI hormones.Endogenous 14-amino acid peptide (also a 28-amino acid form) produced in the hypothalamus, pancreatic delta cells, and GI tract. Acts on five receptor subtypes (SSTR1–5). Octreotide and lanreotide are synthetic somatostatin analogs with preferential SSTR2/SSTR5 selectivity and extended half-life. Their therapeutic utility in neuroendocrine tumors derives from SSTR2 overexpression on NET cells. Their investigational use in diabetic retinopathy derives from SSTR2 expression in retinal tissue and somatostatin’s ability to suppress local IGF-1 and VEGF production.