PMC:3724972 / 6826-8523 JSONTXT

{"project":"2_test","denotations":[{"id":"23673515-22065857-63233605","span":{"begin":531,"end":533},"obj":"22065857"},{"id":"23673515-11980628-63233606","span":{"begin":818,"end":820},"obj":"11980628"},{"id":"23673515-11145612-63233607","span":{"begin":859,"end":861},"obj":"11145612"},{"id":"23673515-16801334-63233607","span":{"begin":859,"end":861},"obj":"16801334"},{"id":"23673515-14654798-63233607","span":{"begin":859,"end":861},"obj":"14654798"},{"id":"23673515-11980628-63233607","span":{"begin":859,"end":861},"obj":"11980628"},{"id":"23673515-18477663-63233608","span":{"begin":1303,"end":1305},"obj":"18477663"},{"id":"23673515-11145612-63233609","span":{"begin":1677,"end":1679},"obj":"11145612"}],"text":"Overview\nGenerally, somatostatin analogs are designed to emulate the structure of native somatostatins, while lacking the enzyme degradation sites of the native molecules. Octreotide and lanreotide (Fig. 2a, b) have long been used for treatment of acromegaly, hyperthyroidism, and gastroenteropancreatic neuroendocrine tumors. Another novel analog, somatoprim (DG3173), selectively binds sstr subtypes 2, 4, and 5 and has demonstrated suppression of growth hormone in octreotide-non-responsive cultured human somatotroph adenomas [34]. However, the clinical utility of somatoprim has not yet been evaluated.\nFig. 2 Chemical structures of somatostatin-14, octreotide, and pasireotide. Adapted from Bruns C, Lewis I, Briner U, Meno-Tetang G, Weckbecker G (2002) ©European Journal of Endocrinology, volume 146, page 710 [38]. Reproduced with permission\nTable 1 [35–38] summarizes binding affinities (IC50) for somatostatin-14 and for 5 somatostatin analogs. Somatastain-14 binds to all 5 sstrs with similar binding affinity, while both octreotide and lanreotide exhibit relative selectivity for sstr2. This selectivity profile is consistent with studies that have ascribed the efficacy of octreotide and lanreotide at inhibiting growth hormone release from somatotroph adenomas to their activity at sstr2 [39].\nTable 1 Binding affinities (IC50) for various somatostatin analogs at the 5 known somatostatin receptor subtypes\nBinding affinity (IC50), nmol/L\nAnalog sstr1 sstr2 sstr3 sstr4 sstr5\n Somatostatin-14 0.93 0.15 0.56 1.5 0.29\n Octreotide 280 0.38 7.1 \u003e1000 6.3\n Lanreotide 180 0.54 14 230 17\n Vapreotide \u003e1000 5.4 31 45 0.7\n Pasireotide 9.3 1.0 1.5 \u003e100 0.16\n Somatoprim [35] \u003e1000 3 \u003e100 7 6"}