Prenatal @entity2206 exposure in XXXX @entity19 : low-dose developmental effects and internal dosimetry.

@entity19 @entity2206 @entity2207 @entity2659
@entity2206 ( @entity2207 ) is an environmental contaminant that causes adverse developmental effects in laboratory animals. To investigate the low-dose effects of @entity2207 on offspring, timed-pregnant @entity2659 @entity19 were gavage dosed with @entity2207 for all or half of gestation. In the full-gestation study, @entity19 were administered 0, 0.3, 1.0, and 3.0 mg @entity2207 /kg body weight (BW)/day from gestation days (GD) 1-17. In the late-gestation study, @entity19 were administered 0, 0.01, 0.1, and 1.0 mg @entity2207 /kg BW/day from GD 10-17. Exposure to @entity2207 significantly (p < 0.05) increased offspring relative liver weights in all treatment groups in the full-gestation study and in the 1.0 mg @entity2207 /kg group in the late-gestation study. In both studies, the offspring of all @entity2207 -treated dams exhibited significantly stunted mammary epithelial growth as assessed by developmental scoring. At postnatal day 21, mammary glands from the 1.0 mg/kg GD 10-17 group had significantly less longitudinal epithelial growth and fewer terminal end buds compared with controls (p < 0.05). Evaluation of internal dosimetry in offspring revealed that @entity2207 concentrations remained elevated in liver and serum for up to 6 weeks and that brain concentrations were low and undetectable after 4 weeks. These data indicate that @entity2207 -induced effects on mammary tissue (1) occur at lower doses than effects on liver weight in @entity2659 @entity19 , an observation that may be strain specific, and (2) persist until 12 weeks of age following full-gestational exposure. Due to the low-dose sensitivity of mammary glands to @entity2207 in @entity2659 @entity19 , a no observable adverse effect level for mammary developmental delays was not identified in these studies.
