... high-affinityligand125I-labelled NDP MSH was used f or saturationanalysis. Competition binding analysis was performed usingNDP -MSH, a -MSH, b -MSH, c1 -MSH, ACTH(1–17),ACTH(1–24), MTII and ... constant0.6 nMconcentration of125I-labelled NDP MSH and serialdilutions of competing u nlabelled ligands: N DP -MSH, a -MSH, b -MSH, c1 -MSH, ACTH(1–24), ACTH(1–17),MTII, and HS024 (Neosystem). ... stimulation with a -MSH, ACTH andc1 -MSH. The results are shown in Fig. 5. These threesubstances were able to activate the a ccumulation of cAMPwith considerable EC50values. a -MSH and ACTH hadEC50values...