The metabolism and conjugation of 15 alpha-hydroxylated phenolic steroids by the rabbit.

The rabbit converts administered 15α-hydroxyestrone and 15α-hydroxyestradiol-17β to 15α-hydroxy-estradiol-17α. This conversion is incomplete when large amounts of the steroids are injected. All three of the 15α-hydroxylated estrogens are excreted as monoglucuronides, and no evidence was found for the formation of double conjugates or of N-acetylglucosaminides. The rabbit therefore differs from the human in that it does not transfer N-acetylglucosamine to the 15α-hydroxyl group of the phenolic steroids, and the presence of this group prevents the usual transfer of this sugar to the 17α-hydroxyl group.