Effect of Sst, Oct and Morph on U266 cell line viability. Exponentially growing cells were seeded and incubated for 24, 48 or 72 h with (A) somatostatin (Sst), (B) octreotide (Oct), (C) Sst alone or combined with 10 μM morphine (Morph). The SSTR antagonist cyclosomatostatin (Css) was also included. U266 cell viability was determined using the XTT assay and data were normalized to absorbance values obtained in control cells. Data are mean ± S.E.M of 5 to 7 different experiments performed in triplicate.