A novel measuring method (electroimmunoassay) of 17β-estradiol (E2) in urine or blood was proposed on the basis of a competition between E2 and a labeled E2 against an immobilizing antibody. To evaluate the principle, 3-{4-[17β-hydroxy-1, 3, 5 (10)-estratrien-3- yloxy] butyldisulfanyl}-N-(6, 7, 9, 10, 12, 13, 15, 16-octahydro-5, 8, 11, 14, 17- pentaoxabenzocyclopentadecen-2-yl) succinamic acid () was designed and synthesized ...