title: Distribution of isoflavones in samples of serum, liver and mammary glands of rats or pigs fed dietary isoflavones.
abstract: OBJECTIVE
  There has been great interest in the potential beneficial and adverse health effects of dietary isoflavones. Determination of tissue concentrations of isoflavone metabolites provides an insight into the potential bioactivity of dietary isoflavones. However, data on the distribution of isoflavones in animal models fed dietary isoflavones are limited. In this study, additional data on the distribution of isoflavones in serum and/or tissues of rats and pigs fed dietary isoflavones were generated.
  
  
  METHODS
  Rats (male and female) were fed a casein control diet (containing no isoflavones) and an isoflavone-supplemented diet (containing an alcohol-washed soy protein isolate plus NOVASOY, providing a total of 1,047 mg/kg of total isoflavones). Female pigs were fed a control diet (without soy) containing 17.5 mg/kg of isoflavones, a soy diet containing 582.8 mg/kg of isoflavones or a soy diet supplemented with a daily dose of 2.3 g (equivalent to 42.0 and 14.5 mg/kg of body weight at the onset and end of treatment, respectively) of crystalline genistein. The concentrations of isoflavones in serum and tissues (liver and mammary gland) and in tissues (liver and mammary gland) of pigs were determined via a sensitive and rapid method using liquid chromatography/mass spectrometry.
  
  
  RESULTS
  Rats fed the control diet containing no isoflavones had nondetectable levels of isoflavone metabolites in serum, liver and mammary gland samples. Rats fed the isoflavone-supplemented diet had the greatest levels of equol, followed by genistein, daidzein and glycitein, respectively, in their serum, livers and mammary glands. The concentrations of total isoflavones (daidzein, equol and genistein plus glycitein) in serum were significantly (p < 0.05) greater in male rats vs. female rats, but the reverse was true in the case of livers. Concentrations of daidzein, equol, genistein and glycitein were lowest (p < 0.05) in the livers of pigs fed the control diet, and in the mammary glands of female pigs there was only an effect of feeding soy plus genistein on the concentrations of daidzein and equol (p <0.05).
  
  
  CONCLUSIONS
  The current data therefore show gender as well as species differences in the tissue distribution of isoflavones.
authors.affiliation: Nutrition Research Division, Health Canada, Ottawa, Ont., Canada. Sarwar.Gilani@hc-sc.gc.ca
authors.forename: G Sarwar
authors.initials: GS
authors.lastname: Gilani
authors.forename: Chantal
authors.initials: C
authors.lastname: Farmer
authors.forename: Monica
authors.initials: M
authors.lastname: Dyck
authors.forename: Patrick
authors.initials: P
authors.lastname: Robertson
authors.forename: Jagroop
authors.initials: J
authors.lastname: Dahiya
authors.forename: Estatira
authors.initials: E
authors.lastname: Sepehr
authors.forename: Li
authors.initials: L
authors.lastname: Fan
authors.forename: Helen
authors.initials: H
authors.lastname: Nicolidakis
authors.forename: Ivan
authors.initials: I
authors.lastname: Curran
authors.forename: Gerard M
authors.initials: GM
authors.lastname: Cooke
mesh_terms: D000818:Animals; D001835:Body Weight; D002853:Chromatography, Liquid; D004032:Diet; D019587:Dietary Supplements; D060754:Equol / Q000097:blood; D005260:Female; D019833:Genistein / Q000097:blood*; D007529:Isoflavones / Q000097:blood*; D008099:Liver / Q000187:drug effects* / Q000378:metabolism; D008297:Male; D008321:Mammary Glands, Animal / Q000187:drug effects* / Q000378:metabolism; D013058:Mass Spectrometry; D051381:Rats; D017207:Rats, Sprague-Dawley; D030262:Soybean Proteins / Q000008:administration & dosage; D013552:Swine
chemical_list: D007529:Isoflavones; D030262:Soybean Proteins; D060754:Equol; C004742:daidzein; C086566:glycitein; D019833:Genistein