| Abstract: | Four analogs of human beta-endorphin (beta h-EP) were synthesized by the solid-phase method: Gln8,31]-beta h-EP(I), Arg8,Gln31]-beta h-EP(II), Ala8,Gln31]-beta h-EP (III), and Val8, Gln31]-beta h-EP(IV). Radioreceptor binding assay with use of tritiated beta h-EP as primary ligand gave relative potencies as follows: beta h-EP, 100; I, 200;II, 150;III, 150;IV, 120. Relative potencies in an analgesic assay were: beta h-EP, 100; I,236;II, 254;III, 116;IV, 121. The side-chain of Glu-8 in beta h-EP can be replaced by a variety of structures without diminishing biological activity. |
