Octreotide

A synthetic eight-amino-acid mimic of the natural hormone somatostatin, the body's main 'off switch' for hormone secretion. It binds somatostatin receptors SSTR2 and SSTR5 with high affinity, clamping down on adenylate cyclase and calcium channels inside hormone-producing cells, which throttles the release of growth hormone, glucagon, insulin, gastrin, and several gut hormones. In acromegaly it drops growth hormone output from the pituitary tumor, lowering IGF-1. It also slows gut motility and reduces splanchnic blood flow, calming carcinoid-related diarrhea. FDA-approved for multiple indications including acromegaly and carcinoid syndrome.