Figure 5

Antagonistic effect of 11 on the inhibition of forskolin-stimulated intracellular cAMP accumulation in SK-N-MC cells. Cells were incubated for 30 min with 10 μM forskolin in the presence of [Leu³¹, Pro³⁴]-PYY (LP-PYY) at concentrations ranging between 0.01 nM and 20 μM alone (solid circle) or with 10 μM forskolin in the presence of LP-PYY at concentrations ranging between 0.01 nM and 20 μM supplemented with a fixed concentration of 20 μM of the analog 11 (solid square). Compound 11 behaves like an antagonist since it shifts the dose response curve of LP-PYY to the right. Compound 11 given alone at a concentration of 20 μM has no effect on the accumulation of forskolin-stimulated cAMP (solid triangle).