The three dominant oxidative biotransformations of estradiol were examined in 10 normal women and 33 females with breast cancer by using a recently devised radiometric method. Estradiol tracers, labeled with 3H specifically in the 17α, C-2, or 16α position, were used to measure both the rate and extent of 17β-ol oxidation (the initial metabolic step) and the subsequent 2- and 16α-oxidative reactions. The mean ± SEM values for the extent of estradiol metabolism at these three specific sites were 76.9 ± 5.3%, 31.1 ± 4.0%, and 9.3 ± 0.8%, respectively, in normal subjects. Corresponding data in patients with breast cancer - i.e., 73.0 ± 4.2%, 32.7 ± 2.7%, and 14.9 ± 1.5% - revealed a significantly greater extent of 16α-hydroxylation in the latter population. Because the 16α-hydroxylated compounds (including estriol) are themseleves potent estrogens, these changes may have important hyperestrogenic consequences that could have a bearing on the etiology of the disease.
|Original language||English (US)|
|Number of pages||5|
|Journal||Proceedings of the National Academy of Sciences of the United States of America|
|Issue number||9 I|
|State||Published - 1982|
ASJC Scopus subject areas