Effect of dietary soy isoflavone aglycones on the urinary 16 alpha-to-2-hydroxyestrone ratio in C3H/HeJ mice

Citation
T. Kishida et al., Effect of dietary soy isoflavone aglycones on the urinary 16 alpha-to-2-hydroxyestrone ratio in C3H/HeJ mice, NUTR CANCER, 38(2), 2000, pp. 209-214
Citations number
42
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Oncology,"Onconogenesis & Cancer Research
Journal title
NUTRITION AND CANCER-AN INTERNATIONAL JOURNAL
ISSN journal
0163-5581 → ACNP
Volume
38
Issue
2
Year of publication
2000
Pages
209 - 214
Database
ISI
SICI code
0163-5581(2000)38:2<209:EODSIA>2.0.ZU;2-Z
Abstract
Estradiol is metabolized through two mutually exclusive pathways. 2-Hydroxy estrone (2-OHEI) is antiestrogenic, while 16 alpha -hydroxyestrone (16 alph a -OHEI) is a potent estrogen. It is suggested that a high urinary 16 alpha -OHEI-to-2-OHEI rato is a biomarker of increased mammary tumor risk. Mice were fed one of the test diets for 21 days. Indole-3-carbinol (2,500 mg/kg diet) increased the cytochrome P-450 content of hepatic microsomes and live r weight and reduced the urinary 16 alpha -OHEI-to-2-OHEI ratio in comparis on with the respective value in the control mice. Fermented soy extract (10 0, 200, or 400 mg isoflavonoid/kg diet), genistein (200 mg/kg diet), and da idzein (200 mg/kg diet) each reduced the urinary 16 alpha -OHEI-to-2-OHEI r atio without increasing the cytochrome P-450 content of hepatic microsomes or liver weight. The combination of genistein and daidzein (100 mg and 100 mg/kg diet) did not have a synergistic effect on the reduction in urinary 1 6 alpha -OHEI-to-2-OHEI ratio. These data suggest that the soy isoflavonoid aglycones genistein and daidzein and indole-3-carbinol each exert a cancer preventive effect by shifting metabolism away from the production of genot oxic metabolites toward the production of inactive metabolites.