Oral cadmium exposure during rat pregnancy: assessment of transplacental micronutrient transport and steroidogenesis at term
Diet is the main source of cadmium (Cd) exposure. Gastrointestinal absorption increases during pregnancy. Cadmium accumulated in the placenta may interfere with nutrient transport to the foetus. Data on the potential of Cd to act as a steroid disruptor of pregnancy are limited. We evaluated the effe...
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Veröffentlicht in: | Journal of applied toxicology 2015-05, Vol.35 (5), p.508-519 |
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Zusammenfassung: | Diet is the main source of cadmium (Cd) exposure. Gastrointestinal absorption increases during pregnancy. Cadmium accumulated in the placenta may interfere with nutrient transport to the foetus. Data on the potential of Cd to act as a steroid disruptor of pregnancy are limited. We evaluated the effects of oral Cd exposure during pregnancy on placental function in micronutrient transfer to the foetus and steroidogenesis in Wistar rats (regular 4‐day cyclers) that mated with unexposed males. Pregnant rats were randomly assigned to a Cd group exposed orally to 50 mg Cd l–1 (CdCl2xH2O dissolved in demineralized water), ≈7.5 mg Cd kg–1 a day, during 20 days of gestation and control (supplied with demineralized water). Non‐pregnant rats were treated under the same experimental conditions. On day 20, all of the rats were killed and samples were taken for element analyses (by electrothermal atomic absorption spectrometry). Progesterone and testosterone were measured in serum and placenta‐derived samples (by immunoenzymometric assay and/or enzyme‐linked immunosorbent assay). In the exposed rats, Cd increased in blood and organs, more in pregnant rats, and in placenta and foetus whereas zinc increased in liver. Iron decreased in maternal organs and in foetus, whereas zinc decreased in maternal kidney and placenta. Liver copper was lower and kidney copper higher in all pregnant vs. non‐pregnant rats. Steroids in serum and placenta did not change. In conclusion, oral Cd exposure during rat pregnancy does not affect progesterone and testosterone at term. Transplacental iron and zinc handover are disrupted, which may put at risk the maintenance of foetal nutrition and viability. Copyright © 2014 John Wiley & Sons, Ltd.
Biomarkers of Cd exposure, maternal and foetal micronutrients, and steroid hormones were evaluated after oral exposure to 50 mg Cd l–1 from pregnancy day 1 to 20. Non‐pregnant rats were exposed under the same conditions. The Cd load was higher in pregnant rats. Progesterone and testosterone in placenta and serum were unchanged. Liver zinc increased in all exposed rats. Zinc decreased in maternal kidney and placenta, iron decreased in the maternal organs and foetus; hence micronutrient handover to the foetus was disrupted. |
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ISSN: | 0260-437X 1099-1263 |
DOI: | 10.1002/jat.3055 |