Pharmaceutical Sciences Faculty Publications

Past Oral Contraceptive Use and Current Dietary Soy Isoflavones Influence Estrogen Metabolism in Postmenopausal Monkeys (Macaca Fascicularis)

Document Type

Article

Publication Date

10-1-2008

Journal Title

Cancer Epidemiology, Biomarkers & Prevention

ISSN

1055-9965

Volume

17

Issue

10

First Page

2594

Last Page

2602

DOI

10.1158/1055-9965.EPI-08-0278

PubMed ID

18843000

PubMed Central® ID

PMC2724961

Abstract

Estrogen metabolism may play an important role in mammary carcinogenesis in postmenopausal women. We evaluated the effects of prior oral contraceptive (OC) treatment and current soy isoflavone consumption on endogenous estrogen metabolite concentration and biomarkers of tissue estrogen exposure in a monkey model. One hundred eighty-one female cynomolgus macaques were randomized to receive OC or placebo for 26 months premenopausally, then ovariectomized and randomized to one of three diets for 36 months: an isoflavone-depleted soy protein isolate (Soy-) diet, a diet containing soy protein isolate with a human equivalent of 129 mg isoflavone/d (Soy+), or a Soy- diet supplemented with conjugated equine estrogens (CEE+) at a human equivalent dose of 0.625 mg/d. Reverse-phase high-performance liquid chromatography directly coupled with tandem mass spectrometry was used to measure the concentrations of estrogen species in urine samples. Generally, prior OC treatment was associated with significantly reduced urinary estrogen metabolites (25-55% reduction; P

Keywords

Biomarkers, chromatography, high pressure liquid, contraceptives, Oral, endometrium, estrogens, isoflavones, macaca fascicularis, mammary glands, postmenopause, soybean, proteins, spectrometry, mass, electrospray ionization

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