Genistein Exposure During the Early Postnatal Period Favors the Development of Obesity in Female, But Not Male Rats

• DOI: 10.1093/toxsci/kft331
• Publication Date: 2013-12-22T01:24:33Z
• Authors: Rita S. Strakovsky; Stéphane Lezmi; Jodi A. Flaws; Susan L. Schantz; Yuan-Xiang Pan; William G. Helferich
• Keywords: Sex steroid

Genistein (Gen), the primary isoflavone in soy, has been shown to adversely affect various endocrine-mediated endpoints rodents and humans. Soy formula intake by human infants associated with early age at menarche decreased female-typical behavior girls. Adipose deposition expansion are also hormonally regulated Gen alter these processes. However, little is known about impact of early-life soy on metabolic homeostasis adulthood. The current study examined exposure adulthood body composition (by magnetic resonance imaging) molecular signals mediating adipose expansion. From postnatal day (PND) 1 22, rat pups were daily orally dosed 50mg/kg mimic blood levels fed formula. Female but not male Gen-exposed rats had increased fat/lean mass ratio, fat mass, adipocyte size number, muscle fiber perimeter. PND22 females, males, expression adipogenic factors, including CCAAT/enhancer binding protein alpha (Cebpα), beta (Cebpβ), peroxisome proliferator-activated receptor gamma (Pparγ). Furthermore, Wingless-related MMTV integration site 10b (Wnt10b), a critical regulator cell fate determination, was hypermethylated females. These data suggest that developmental gender-specific effects adiposity closely parallel postweaning high-fat diet underscore importance considering timing gender when establishing safety recommendations for dietary intake.