Figure 4. 135PAM1 dose-dependently augments the inhibition of CRE activity of probe (EC₂₀) concentrations of Relaxin-3_NH2 in cells expressing RXFP3, but not RXFP4.

As RXFP3 and RXFP4 are G_i/o-linked receptors, experiments analogous to Fig. 2 were performed without the use of a chimeric G protein, comparing cAMP response element (CRE) activity in cells expressing RXFP3 (panels A and C) to closely related receptor RXFP4 (panels B and D). RXFP3 or RXFP4 receptors were expressed in SK-N-MC cells co-expressing a CRE construct linked to β-galactosidase expression. Forskolin (5 µM) was used to stimulate CRE activity and ascending doses of 135PAM1 were added to probe (EC₂₀) concentrations of Relaxin-3_NH2 (A and B) or Relaxin-3_OH (C and D).