title: Regulation of male sex hormone levels by soy isoflavones in rats.
abstract: Several studies have suggested that soybean intake is associated with a lower risk of prostate cancer. However, the mechanism of prostate cancer prevention by soybeans remains unclear. Because prostate cancer is reported to have an association with an increased level of dihydrotestosterone (DHT) and soybean isoflavones are known to inhibit 5 alpha-reductase, which is involved in the conversion of testosterone to DHT, the effects of soybean extract and isoflavones on the plasma levels of male sex hormones were investigated using male rats. In Experiment I, Sprague-Dawley rats were fed diets with and without soy flour; in Experiment II, rats were fed diets containing 2% soy methanol extract or 0.2% semipurified isoflavones or a control diet. The study showed a reduction of plasma DHT along with an increase in total plasma androgen in rats fed soy flour or semipurified isoflavones for 1 wk. These results suggest that soy isoflavone intake may reduce plasma DHT level.
authors.affiliation: Department of Animal Science and Biotechnology, Kyungpook National University, Taegu 702-701, South Korea.
authors.forename: Mi-Ae
authors.initials: MA
authors.lastname: Yi
authors.forename: Hyun M
authors.initials: HM
authors.lastname: Son
authors.forename: Jung-Soon
authors.initials: JS
authors.lastname: Lee
authors.forename: Chong-Suk
authors.initials: CS
authors.lastname: Kwon
authors.forename: Jin Kyu
authors.initials: JK
authors.lastname: Lim
authors.forename: Young Keun
authors.initials: YK
authors.lastname: Yeo
authors.forename: Young Sik
authors.initials: YS
authors.lastname: Park
authors.forename: Jong-Sang
authors.initials: JS
authors.lastname: Kim
mesh_terms: D000818:Animals; D013196:Dihydrotestosterone / Q000097:blood*; D007529:Isoflavones / Q000097:blood / Q000494:pharmacology*; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D013025:Glycine max
chemical_list: D007529:Isoflavones; D013196:Dihydrotestosterone; C065753:isoflavanone