Although oestrone (Butenandt, 1929; Doisy,
Veler and Thayer, 1929), oestriol (Marrian,
1930) and oestradio1-17ß (Wintersteiner, Schwenk
and Whitman, 1935) have been isolated from
biological material for some time, their
metabolic interrelationships have not been fully
studied until recently.
From their relative biological potencies
the suggestion was put forward that oestradiol17ß is the active primary hormone produced by
the ovaries and that this is readily converted to
oestrone. Oestriol was thought to be a deactivated metabolite of one or both of these.
The liver is involved in this deactivation
process (see Mayer, 1952).