Phytoestrogen content of purified, open-and closed-formula laboratory animal diets
JE Thigpen, KDR Setchell, KB Ahlmark… - Comparative …, 1999 - ingentaconnect.com
JE Thigpen, KDR Setchell, KB Ahlmark, J Locklear, T Spahr, GF Caviness, MF Goelz…
Comparative Medicine, 1999•ingentaconnect.comBackground and Purpose: Phytoestrogens exert estrogenic effects on the central nervous
system, induce estrus, and stimulate growth of the genital tract of female animals. Over 300
plants and plant products, including some used in laboratory animal diets, contain
phytoestrogens. Therefore, the source and concentration of phytoestrogens in rodent diets
were determined. Methods: Twelve rodent diets and six major dietary ingredients were
assayed for phytoestrogens (daidzein, genistein, formononetin, biochanin A, and …
system, induce estrus, and stimulate growth of the genital tract of female animals. Over 300
plants and plant products, including some used in laboratory animal diets, contain
phytoestrogens. Therefore, the source and concentration of phytoestrogens in rodent diets
were determined. Methods: Twelve rodent diets and six major dietary ingredients were
assayed for phytoestrogens (daidzein, genistein, formononetin, biochanin A, and …
Background and Purpose
Phytoestrogens exert estrogenic effects on the central nervous system, induce estrus, and stimulate growth of the genital tract of female animals. Over 300 plants and plant products, including some used in laboratory animal diets, contain phytoestrogens. Therefore, the source and concentration of phytoestrogens in rodent diets were determined.
Methods
Twelve rodent diets and six major dietary ingredients were assayed for phytoestrogens (daidzein, genistein, formononetin, biochanin A, and coumestrol), using high-performance liquid chromatography. Three rodent diets recently formulated to reduce phytoestrogen content also were assayed.
Results
Formononetin, biochanin A, and coumestrol were not detected. Soybean meal was the major source of daidzein and genistein; their concentrations were directly correlated to the percentage of soybean meal in each diet.
Conclusions
High, variable concentrations of daidzein and genistein are present in some rodent diets, and dietary phytoestrogens have the potential to alter results of studies of estrogenicity. Careful attention should be given to diet phytoestrogen content, and their concentration should be reported. A standardized, openformula diet in which estrogenic substances have been reduced to levels that do not alter results of studies that are influenced by exogenous estrogens is recommended.
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