MOLECULAR-CLONING OF 2 RECEPTORS FROM RAT-BRAIN WITH HIGH-AFFINITY FOR SALMON-CALCITONIN

Two receptors with high affinity for salmon calcitonin were cloned fro m the nucleus accumbens region of rat brain. The deduced 479 amino aci d sequence of cDNA clone L2175-D20 (designated C1a receptor) is 78% an d 66% identical with those reported for human and porcine calcitonin r eceptors, respectively. Clone U3237-A2 codes for a receptor (designate d C1b) that is identical to C1a except fora 37 aminoacid insert in the second extracellular domain. COS-7 cells transfected with either tran script bound [I-125]salmon calcitonin with high affinity (K(d) = 8 pM for C1a; K(d) = 48 pM for C1b) and responded to salmon calcitonin with increases in cAMP. Tissue distribution studies revealed C1a transcrip t in rat brain, skeletal muscle, kidney and lung, whereas C1b was pred ominantly found in brain.