An SST2 antagonist (IC50 = 2.62 nM); selective for SST2 over SST1, SST3, SST4, and SST5 (IC50s = 3,890, 851, 1,737, and 331 nM, respectively); inhibits SST-induced increases in EAR in CHO-K1 cells expressing recombinant human SST2 (pKB = 7.92) and [35S]GTPγS binding in CHO-K1 cell membranes expressing recombinant human SST2 (pKB = 7.81)