Abstract Urinary metabolites of the new progestagen STS 557 (17α-cyanomethyl-17-hydroxy- 4, 9-estradien-3-one) were isolated and characterized following oral administration of the 14α, 15α-tritium labelled compound to dogs and rats. 17α-Cyanomethyl-11β, 17-dihydroxy- 4, 9-estradien-3-one (11β-OH-STS 557) and 17α-cyanomethyl-1, 3, 5 (10), 9 (11)- estratetraene-3, 17-diol were identified by comparison with synthesized reference ...
