In vitro pharmacological profile of nonpeptide CRF1 receptor antagonists, CRA1000 and CRA1001

We investigated pharmacological properties of CRA1000 (2-(N-(2-methylthio-4-isopropylphenyl)-N-ethylamino-4-(4-(3-fluorophenyl)-1,2,3,6-tetrahydropyridin-1-yl)-6-methylpyrimidine) and CRA1001 (2-(N-(2-bromo-4-isopropylphenyl)-N-ethylamino-4-(4-(3-fluorophenyl)-1,2,3,6-tetrahydropyridin-1-yl)-6-methylpyrimidine), novel and selective antagonists for the corticotropin-releasing factor, (CRF1) receptor. Both CRA1000 and CRA1001 inhibited [I-125]ovine CRF binding to membranes of COS-7 cells expressing the rat CRF1 receptor with IC50 values of 30 and 38 nM, respectively, without affecting [(12)5I]sauvagine binding to membranes of COS-7 cells expressing the rat CRF2 alpha receptor. CRF elicited intracellular cyclic AMP (cAMP) accumulation in AtT-20 cells which express the CRF1 receptor but not the CRF2 receptor, and COS-7 cells expressing CRF1 or CRF2 alpha receptors. The CRF-induced cAMP accumulation was inhibited by both CRA1000 and CRA1001, concentration-dependently, in AtT-20 cells and COS-7 cells expressing the CRF1 receptor, while these compounds did not attenuate the CRF response in COS-7 cells expressing the CRF2 alpha receptor. CRF increased adrenocorticotropin (ACTH) secretion from AtT-20 cells, and CRA1000 and CRA1001 inhibited CRF-induced ACTH secretion, concentration-dependently, as did other CRF1 receptor antagonists. These results show that both CRA1000 and CRA1001 are potent and selective CRF1 receptor antagonists. (C) 1999 Elsevier Science B.V. All rights reserved.