Figure 3

cAMP inhibition upon activation of SSTR2/SSTR3. Mono- and/or cotransfected expressing SSTR2 and SSTR3 were pre-treated with 3-isobutyl-1-methylxanthine (0.5 mM) for 30 min followed by addition of FSK (20 μM) in the presence or absence of SST (1, 50 nM and 1 μM), and receptor-specific agonists L-779976 (10 and 100 nM) and L-796778 (25 and 50 nM), or as indicated for 30 min at 37°C and processed for cAMP assay. Note the significant inhibition of FSK-stimulated cAMP in the presence of SST and receptor-specific agonists; an indication that SSTR2/SSTR3 complex in cotransfected cells is functionally active, albeit at a lesser degree than the monotransfectants. Data represent mean ± S.D of three independent experiments.