FIGURE 1.  sst₂ internalization is induced by various agonists and is abolished by antagonist Coy-14. HEK-sst₂ cells were treated for 30 min either with vehicle (no peptide [A]) or with various agonists at concentrations inducing submaximal internalization effect (100 nmol/L [B and C] and 10 nmol/L [D–F]). (H–L) Cells treated with same agonists at same concentrations as in B–F but in presence of excess of specific sst₂-antagonist Coy-14 (5 [H], 10 [I], and 1 [J–L] µmol/L). Effect of antagonist alone (10 µmol/L [G]) is also shown. After incubation with peptides, cells were processed for immunocytochemistry. Clear punctate perinuclear staining is detectable for all tested agonists. This punctate staining is efficiently abolished by excess of antagonist Coy-14. Antagonist alone has no effect on internalization.