ABSTRACT
Chronic kidney disease (CKD) affects over 15 % of the adults in the United States. Pregnant women with CKD present an additional challenge in that they are at increased risk for adverse events such as preterm birth. Exposure to environmental toxicants, such as methylmercury, may exacerbate maternal disease and increase the risk of adverse fetal outcomes. We hypothesized that fetuses of mothers with CKD are more susceptible to accumulation of methylmercury than fetuses of healthy mothers. The current data show that when mothers are in a state of renal insufficiency, uptake of mercury in fetal kidneys is enhanced significantly. Accumulation of Hg in fetal kidneys may be related to the flow of amniotic fluid, maternal handling of Hg, and/or underdeveloped mechanisms for cellular export and urinary excretion. The results of this study indicate that renal insufficiency in mothers leads to significant alterations in the way toxicants such as mercury are handled by maternal and fetal organs.
Subject(s)
Environmental Pollutants/pharmacokinetics , Fetus/metabolism , Maternal-Fetal Exchange , Mercury/metabolism , Methylmercury Compounds/pharmacokinetics , Renal Insufficiency, Chronic/metabolism , Amniotic Fluid/chemistry , Animals , Brain/metabolism , Environmental Pollutants/toxicity , Feces/chemistry , Female , Humans , Infant, Newborn , Kidney/drug effects , Kidney/metabolism , Kidney/pathology , Male , Mercury/blood , Mercury/urine , Methylmercury Compounds/toxicity , Placenta/chemistry , Pregnancy , Rats, Wistar , Tissue Distribution , Uterus/metabolismABSTRACT
Methylmercury (CH3Hg+), a common environmental toxicant, has serious detrimental effects in numerous organ systems. We hypothesize that a significant physiological change, like pregnancy, can alter the disposition and accumulation of mercury. To test this hypothesis, pregnant and non-pregnant female Wistar rats were exposed orally to CH3Hg+. The amount of mercury in blood and total renal mass was significantly lower in pregnant rats than in non-pregnant rats. This finding may be due to expansion of plasma volume in pregnant rats and dilution of mercury, leading to lower levels of mercury in maternal blood and kidneys.
Subject(s)
Kidney/metabolism , Methylmercury Compounds/blood , Methylmercury Compounds/metabolism , Administration, Oral , Animals , Female , Methylmercury Compounds/administration & dosage , Pregnancy , Rats , Rats, WistarABSTRACT
Methylmercury (CH3Hg+) is an environmental toxicant that may lead to significant pathologies in exposed individuals. The current study assessed the disposition and toxicological effects of 2.5 or 7.5mgkg-1 CH3Hg+, conjugated to cysteine (Cys; Cys-S-CH3Hg) and administered orally to pregnant and non-pregnant Wistar and TR- rats. Rats were euthanized on gestational day 20 and the content of mercury in each fetus, amniotic sac, and placenta was determined. The brain, liver, and kidneys were removed from each fetus for estimation of mercury content. From the dams, a sample of blood, kidneys, liver, and brain were removed at the time of euthanasia. The findings from this study indicate that pregnancy leads to significant changes in the handling of mercuric ions, particularly in the liver. Furthermore, there are significant differences in the handling of non-nephrotoxic and nephrotoxic doses of Cys-S-CH3Hg by maternal and fetal organs.
