Hb. Schioth et al., Further pharmacological characterization of the selective melanocortin 4 receptor antagonist HS014: comparison with SHU9119, NEUROPEPTID, 33(3), 1999, pp. 191-196
SHU9119 and HS014 are cyclic MSH analogues which are widely used to elucida
te the physiology behind the various effects of the MSH peptides and their
receptors. We carefully compared the potency of SHU9119 and HS014 in cells
expressing the MC receptor clones. We found that both the peptides are part
ial agonists for the MC1 and MC5 receptors while they are potent antagonist
s for the MC3 and MC4 receptors. In agreement with earlier binding data, we
found that SHU9119 has equal potency for the MC3 and MC4 receptor whereas
HS014 has at least 10-fold higher potency for the MC4 receptor than the MC3
receptor in cAMP assay. Moreover, we synthesized analogues of HS014 where
the C-terminal was truncated. We found that this C-terminal fragment of HS0
14, in particular the Lys(14) has a major influence on the affinity for the
MC4 receptor without any particular influence on the affinity for the othe
r MC receptors.