the present invention relates to novel somatostatin analogs , dimers thereof , and methods of using the same to treat various diseases . naturally occurring somatostatins , which are also known as somatotropin release - inhibiting factors , have diverse biological effects in many cells and organs 10 throughout the body . they are produced by normal endocrine , gastrointestinal , immune and neuronal cells , as well as by certain tumors : 157 - 198 ; froidevaux , et al ., biopolymers , 66 : 161 - 83 ).