in the presence of 5 mm cacl2 and mgcl2 not only ltc4 ( ic50 10 ( -7 ) m ) , but also ltd4 ( albeit with much lower affinity , ic50 = 6 x 10 ( -5 ) m ) and the srs-a antagonist fpl 55712 ( ic50 = 10 ( -5 ) m ) can compete with 3h-ltc4 for its binding sites .
C0038091
srs-a
C0023542
ltc4