Monkey corticotropin-releasing factor1 receptor: Complementary DNA cloning and pharmacological characterization.

Abstract The full-length complementary DNA (cDNA) of monkey corticotropin-releasing factor type 1 (CRF 1 ) receptor was isolated from a rhesus monkey ( Macaca mulatta ) amygdala cDNA library. The cloned monkey CRF 1 receptor cDNA has 2,374 bp with an open reading frame encoding a 415-amino acid protein. The sequence of the monkey CRF 1 receptor cDNA showed a high degree of sequence identity with other species of CRF 1 receptors, and being 99.5% identical to human CRF 1 receptors. When monkey CRF 1 was expressed into COS-7 cells, high specific binding of [ 125 I]-ovine CRF was observed. CRF and CRF-related peptides inhibited [ 125 I]-ovine CRF binding in a concentration-dependent manner. IC 50 values of ovine CRF, human/rat CRF, sauvagine and urotensin I were 23.5 ± 7.4, 22.7 ± 10.8, 27.5 ± 12.3 and 14.2 ± 7.0 nM, respectively. CRF 1 receptor specific antagonists, such as CP-154,526, SC241 and CRA1000, also inhibited the [ 125 I]-ovine CRF binding, with IC 50 values of 3.9 ± 0.4, 43.5 ± 8.0 and 19.8 ± 2.0 nM, respectively. GTP and its nonhydrolyzed analogue, GTPγS, reduced [ 125 I]-ovine CRF binding, while ATP had a negligible effect, thereby indicating that the monkey CRF 1 receptor belongs to a family of G-protein coupled receptors. CRF and its related peptides increased cyclic AMP formation concentration-dependently in COS-7 cells transiently expressing the monkey CRF 1 receptor. Monkey CRF 1 was expressed abundantly in the pituitary, cerebral cortex, hippocampus, amygdala and cerebellum. Thus the monkey CRF 1 receptor and the human CRF 1 receptor have similar molecular and pharmacological characteristics.