ESTROGEN BIOSYNTHESIS - 2-BETA-HYDROXY-19-OXOANDROST-4-ENE-3,17-DIONEREVISITED

Current evidence is consistent with the view that biosynthesis of estr ogens by human microsomal placental aromatase proceeds through several different pathways. One of the proposed mechanisms of aromatization o f androgens involves the intermediacy of 2beta-hydroxy-19-oxoandrost-4 -ene-3,17-dione 1a. It is shown that incubation of 2beta[(OH)-O-18]-1b with placental aromatase gave (HCOOH)-O-18 which differs from previou s observations. The incorporation of isotopic oxygen in the formic aci d is consistent with the view that one of the alternative routes of es trogen elaboration may involve a 2beta,19-dioxygenated androgen.