Fig. 1.

Agonist-specific effects on sst2A receptor internalization in pancreatic cells. AR42J cells were incubated at 37 C with 100 nm SS14, 1 μm SOM230, or 1 μm KE108 for the times shown. After agonist treatment, cells were rinsed with cold PBS, fixed, and permeabilized as described in Materials and Methods. sst2A receptors were immuno-labeled with receptor antibody followed with DTAF-conjugated donkey antirabbit IgG, and receptor distribution was then assessed by confocal microscopy. The images shown are representative of results from at least three independent experiments. The right panel of each pair of images shows an enlargement of a typical cell observed in the left panel. Although SS14 elicits pronounced receptor internalization within 2 min, SOM230 and KE108 have a much smaller effect on receptor endocytosis with substantial membrane staining still evident after 15 min of peptide treatment.