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Feeding soy protein isolate (SPI) does not result in an estrogenic gene expression profile in the mammary of ovariectomized (OVX) female rats
Author(s) -
Ronis Martin J,
Singhal Rohit,
Shankar Kartik,
Badeaux Jamie,
Badger Thomas M
Publication year - 2010
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.24.1_supplement.212.2
Subject(s) - soy protein , ovariectomized rat , isoflavones , biology , gene , endocrinology , medicine , microarray analysis techniques , cyclin d1 , microarray , gene expression , messenger rna , casein , estrogen , cell cycle , food science , biochemistry
Concerns of increased breast cancer risk in women consuming soy exist because of the perceived estrogenicity of soy isoflavones. Female Sprague‐Dawley rats (N = 20/group) were fed AIN‐93G diets with casein or SPI as the protein from PND30. On PND50 rats were OVX and 10/group infused s.c. with 5 μg/kg/d 17β‐estradiol (E2) to restore physiological levels. On PND64, mammary glands were collected and total mRNA isolated for microarray analysis. Array data were normalized using GeneSpring. Statistical analysis of genes expressed greater than 1.5‐fold revealed 651 genes regulated by E2 (P< 0.05) compared to 27 genes regulated by SPI with only 6 in common between the two treatments. A sub‐set of 164 E2‐regulated genes were further modulated by SPI feeding and 126 genes were only affected by the combination of SPI + E2. Data were confirmed by real time RT‐PCR and suggest that gene signatures of E2 and SPI have little overlap. SPI feeding did significantly modulate responses to E2. In most cases SPI antagonized E2 effects. This included ERβ‐specific genes such as Knsl2 and Top2a and the cell proliferation mediator cyclin D1. USDA CRIS 6251‐51000‐007‐03S.