The phytoestrogen content of rodent diets.

Thigpen, J E; Setchell, Kenneth D.R.; Goelz, Mary F.; Forsythe, Diane B.

doi:10.1289/ehp.107-1566530

Cited by 39 publications

(29 citation statements)

References 23 publications

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Section: Animal Studiesmentioning

confidence: 99%

“…The modified AIN-76A rodent diet (control diet) was chosen because it is essentially phytoestrogen free (32,33). Because phytoestrogens are known to exert estrogenic effects in mice, this avoids potential secondary complications in gender comparisons (32,33). After 1 week, the male and female mice were each divided into three groups (six mice/group): group 1 remained on the control diet; group 2 was switched to a modified AIN-76A rodent diet supplemented with 0.5% phytol (5% calories from fat; diet D01020601; Research Diets, Inc.); group 3 was transferred to a modified AIN-76A rodent diet supplemented with 0.2% clofibric acid (5% calories from fat; diet D01020602; Research Diets, Inc.).…”

Section: Animal Studiesmentioning

confidence: 99%

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Sexually dimorphic metabolism of branched-chain lipids in C57BL/6J mice

Atshaves

Payne

McIntosh

et al. 2004

Journal of Lipid Research

118

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Despite the importance of branched chain lipid oxidation in detoxification, almost nothing is known regarding factors regulating peroxisomal uptake, targeting, and metabolism. One peroxisomal protein, sterol carrier protein-x (SCP-x), is thought to catalyze a key thiolytic step in branched chain lipid oxidation. When mice with substantially lower hepatic levels of SCP-x were tested for susceptibility to dietary stress with phytol (a phytanic acid precursor and peroxisome proliferator), livers of phytol-fed female but not male mice i ) accumulated phytol metabolites (phytanic acid, pristanic acid, and ⌬ -2,3-pristanic acid); ii ) exhibited decreased fat tissue mass and increased liver mass/ body mass; iii ) displayed signs of histopathological lesions in the liver; and iv ) demonstrated significant alterations in hepatic lipid distributions. Moreover, both male and female mice exhibited phytol-induced peroxisomal proliferation, as demonstrated by liver morphology and upregulation of the peroxisomal protein catalase. In addition, levels of liver fatty acid binding protein, along with SCP-2 and SCP-x, increased, suggesting upregulation mediated by phytanic acid, a known ligand agonist of the peroxisomal proliferator-activated receptor ␣ . In summary, the present work establishes a role for SCP-x in branched chain lipid catabolism and demonstrates a sexual dimorphic response to phytol, a precursor of phytanic acid, in lipid parameters and hepatotoxicity.

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Section: Animal Studiesmentioning

confidence: 99%

Section: Animal Studiesmentioning

confidence: 99%

Sexually dimorphic metabolism of branched-chain lipids in C57BL/6J mice

Atshaves

Payne

McIntosh

et al. 2004

Journal of Lipid Research

118

View full text Add to dashboard Cite

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“…Although it is known that isoflavones are consistently high in the serum and urine of humans who regularly consume soy protein foods (Adlercreutz et al, 1991(Adlercreutz et al, , 1993bMorton et al, 1994;Murphy et al, 1982;Setchell et al, 1997Setchell et al, , 1998, it is less well appreciated in the scientific community that commercial diets formulated with soy meal (Drane et al, 1975;Murphy, 1982;Thigpen et al, 1999aThigpen et al, , 1999b) cause rodents to have sustained high steady-state serum isoflavone concentrations. Such effects have tremendous implications for animal experiments, particularly when biochemical or morphological end-points are being measured that may be influenced by the hormonal or nonhormonal properties of isoflavones (Boettger-Tong et al, 1998;Drane et al, 1975).…”

mentioning

confidence: 99%

Animal Models Impacted by Phytoestrogens in Commercial Chow: Implications for Pathways Influenced by Hormones

Brown

Setchell

2001

Laboratory Investigation

271

239

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SUMMARY:It is generally not known that most commercial rodent diets are formulated with soy protein and deliver large daily doses of isoflavones to animals throughout their lifespan, including the in utero period. Here, we demonstrate that isoflavones are bioavailable and show that commercial rodent diets universally used by animal facilities lead to very high steady-state serum isoflavone concentrations in adult rats (2613 Ϯ 873 ng/mL) and mice (2338 Ϯ 531 ng/mL), exceeding the animal's endogenous estrogen level by 30,000-to 60,000-fold. We demonstrate the maternal-fetal intrauterine transfer of isoflavones in animals fed a standard Purina 5001 soy-containing diet and show that newborn rat pups have high serum isoflavones levels (540 Ϯ 174 ng/mL) that are maintained throughout the suckling period by passage of isoflavones into maternal milk. These findings have profound implications for all animal experiments, including multigenerational studies and studies of transgenic animals, especially if biochemical or morphological end-points are influenced by the hormonal or nonhormonal properties of phytoestrogens. These compounds have the potential to modulate genotypic and phenotypic expression in general, and therefore, all investigators should be vigilant to the phytoestrogen composition of commercial rodent diets because there is a history of potent biological effects in larger animals and in humans from high circulating isoflavone concentrations. (Lab Invest 2001, 81:735-747).A lthough phytoestrogens are ubiquitous in the plant kingdom, it is soybeans and foods made with purified soy proteins that are by far the greatest contributors of isoflavones to animal and human diets (Coward et

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“…One week before beginning the dietary studies, male and female mice (2 month of age, 20-30 g) were transferred to a modified AIN-76A phytoestrogen-free control diet (5% calories from fat; D11243, Research Diets, New Brunswick, NJ). This diet was free from any significant amounts of cholesterol and/or phytoestrogens (29) that could complicate any cholesterol-effect and sex-based comparisons (30). Each mouse was housed individually in Techniplast Sealsafe™ IVC cages with external water bottles and wire bar lid holders containing food pellets.…”

Section: Dietary (Cholesterol) Studiesmentioning

confidence: 99%

Overexpression of sterol carrier protein-2 differentially alters hepatic cholesterol accumulation in cholesterol-fed mice

Atshaves

McIntosh

Martin

et al. 2009

Journal of Lipid Research

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Although in vitro studies suggest a role for sterol carrier protein-2 (SCP-2) in cholesterol trafficking and metabolism, the physiological significance of these observations remains unclear. This issue was addressed by examining the response of mice overexpressing physiologically relevant levels of SCP-2 to a cholesterol-rich diet. While neither SCP-2 overexpression nor cholesterol-rich diet altered food consumption, increased weight gain, hepatic lipid, and bile acid accumulation were observed in wild-type mice fed the cholesterol-rich diet. SCP-2 overexpression further exacerbated hepatic lipid accumulation in cholesterol-fed females (cholesterol/cholesteryl esters) and males (cholesterol/ cholesteryl esters and triacyglycerol). Primarily in female mice, hepatic cholesterol accumulation induced by SCP-2 overexpression was associated with increased levels of LDLreceptor, HDL-receptor scavenger receptor-B1 (SR-B1) (as well as PDZK1 and/or membrane-associated protein 17 kDa), SCP-2, liver fatty acid binding protein (L-FABP), and 3a-hydroxysteroid dehydrogenase, without alteration of other proteins involved in cholesterol uptake (caveolin), esterification (ACAT2), efflux (ATP binding cassette A-1 receptor, ABCG5/8, and apolipoprotein A1), or oxidation/ transport of bile salts (cholesterol 7a-hydroxylase, sterol 27a-hydroxylase, Na 1 /taurocholate cotransporter, Oatp1a1, and Oatp1a4). The effects of SCP-2 overexpression and cholesterol-rich diet was downregulation of proteins involved in cholesterol transport (L-FABP and SR-B1), cholesterol synthesis (related to sterol regulatory element binding protein 2 and HMG-CoA reductase), and bile acid oxidation/ transport (via Oapt1a1, Oatp1a4, and SCP-x). Levels of serum and hepatic bile acids were decreased in cholesterol-fed SCP-2 overexpression mice, especially in females, while the total bile acid pool was minimally affected. Taken together, these findings support an important role for SCP-2 in hepatic cholesterol homeostasis. Due to the deleterious effects associated with cholesterol accumulation leading to atherosclerosis, levels of cholesterol in cells and tissues are carefully regulated (1, 2). Cholesterol is derived from both diet and endogenous synthesis, and in order to maintain cholesterol homeostasis, human liver excretes nearly 2 g of cholesterol per day into bile (3). Decreased cholesterol disposal results in hepatic cholesterol accumulation and elevated blood cholesterol, while excessive cholesterol secretion or disproportionate biliary constituents may lead to cholelithiasis and inflammatory gallbladder disease (3, 4). Cholesterol is removed from peripheral tissues to the liver for elimination by oxidation and/or biliary excretion via a process termed reverse cholesterol transport (RCT). Recent novel experiments have elucidated many molecular details of the RCT pathway, including those involving scavenger receptor-B1 (SR-B1)-mediated uptake of HDL-cholesteryl esters and ABC transporter- Abbreviations: 3a-HSD, 3a-hydroxysteroid dehydrogenase; ABCA-...

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The phytoestrogen content of rodent diets.

Cited by 39 publications

References 23 publications

Sexually dimorphic metabolism of branched-chain lipids in C57BL/6J mice

Sexually dimorphic metabolism of branched-chain lipids in C57BL/6J mice

Animal Models Impacted by Phytoestrogens in Commercial Chow: Implications for Pathways Influenced by Hormones

Overexpression of sterol carrier protein-2 differentially alters hepatic cholesterol accumulation in cholesterol-fed mice

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