The structure of the growth hormone release inhibiting factor, somatostatin, has been determined by Brazeau et al., Science, 179, 77(1973). Several techniques for synthesizing somatostatin have been reported in the literature, including the solid phase method of Rivier, J.A.C.S. 96, 2986(1974) and the solution methods of Sarantakis et al., Biochemical Biophysical Research Communications 54, 234(1973) and Immer et al., Helv. Chim. Acta, 57, 730(1974).