Structure and potency of selected lead molecules. (A) Chemical structure of compound MS437: N,N-diisopropyl-2-phenyl-4 quinolinecarboxamide. (B) Chemical structure of compound MS438: Benzyl 6 methyl-2-oxo-4-[4-(trifluoromethyl) phenyl]-1,2,3,4-tetrahydro-5-pyrimidinecarboxylate. (C) Dose–response relationship of bovine thyrotropin (TSH) in CHO cells stably expressing hemagglutinin thyrotropin receptor (HA-TSHR) and pGL4.29 [luc2P/CRE/Hygro]. Luciferase was measured using the substrate Bright-Glo™ and read using an Envision (Perkin Elmer, Inc.) microplate reader. (D) CHO cells stably expressing HA-TSHR and pGL4.29 [luc2P/CRE/Hygro] were also exposed to different concentrations of MS437 and MS438. The data in (C) and (D) were normalized against forskolin. In (C), the bolded and italicized x-axis scale reflects the concentration of bovine TSH represented in moles. This is a representative graph out of three independent experiments.