Pegvisomant is a highly selective growth hormone (GH) receptor antagonist. It is used to treat acromegaly. Unlike dopamine or somatostatin analogs (which inhibit growth hormone secretion), this drug actually blocks the hepatic (GH-mediated) production of insulin like growth factor (IGF-1), which is the main mediator of growth hormone activity. (en)
Somavert selectively binds to growth hormone (GH) receptors on cell surfaces, where it blocks the binding of endogenous GH. This leads to the normalization of serum IGF-1 levels. (en)
Mandayam J. Narasimhan, John A. Anderson, "Process for the large scale production of human growth hormone by serial secondary suspension culture." U.S. Patent US4124448, issued January, 1963. (en)