Effects of oral exposure to arsenobetaine during pregnancy and lactation in Sprague-Dawley rats.

Arsenobetaine (ASB) is the major form of arsenic (As) in seafood sources such as molluscs and fish. Limited data demonstrated that ASB toxicity in mammals is minimal; however, data on possible reproductive effects are lacking. This study investigated the tissue distribution and developmental effects of ASB during pregnancy, early postnatal life, and development to adulthood. Pregnant rats were randomly assigned to 3 cohorts and gavaged daily from gestational day 8 (GD8) with ASB in deionized water at 0, 0.1, 1, or 10 mg/kg body weight (bw)/d. Cohort 1 dams were sacrificed on GD20 (n = 6 per dose group), cohort 2 dams and pups were sacrificed on postnatal day 13 (PND13; n = 4 dams per dose group), and cohort 3 pups (n = 2 dams per dose group) were sacrificed on PND90. Residue analysis detected significant levels of ASB in livers of cohort 1 dams and lower levels in cohort 1 GD20 fetuses, as well as in cohort 2 male and female offspring, indicating placental transfer from the maternal circulation in utero. Trace amounts of ASB in dams' milk were found only in the 10-mg/kg bw/d dose cohort 2 (PND13), demonstrating that lactational transfer was limited. ASB levels in liver varied during pregnancy, lactation, and postweaning, with levels falling rapidly as these physiological states progress. Although transfer of ASB through the placenta to the fetuses and to a limited extent through milk was confirmed, ASB exposure during pregnancy and lactation appeared to produce no teratogenic or deleterious effects on reproductive development.