Description:
<jats:title>Abstract</jats:title>
<jats:p>Radioiron(55Fe) injected directly into the amniotic cavity of 21-day rat fetuses is swallowed and rapidly absorbed by the intestine. The radioisotope is then transported from the intestine and is utilized in the liver and spleen, fetal erythropoietic and iron-storing organs. The level of incorporation in intestine, spleen, and liver, as measured by scintillation counting, is relatively low during the first hour, but increases 3 and 6 hr postinjection. Radioautograms at 6 hr demonstrate extensive labeling in the cytoplasm of absorptive cells in the intestinal mucosa. In liver the 55Fe is observed in parenchymal and reticuloendothelial cells and in developing red cells. Erythroid cells are the principal 55Fe-labeled cells in the spleen. Recirculation of some 55Fe occurred between 55Fe-injected fetuses, maternal organs, and control fetuses. Fetal swallowing of 55Fe within amniotic fluid followed by intestinal absorption of the radioisotope demonstrates the existence of a pathway by which nutrients can be delivered to the fetus. This finding is of potential benefit to the human fetus since a number of compounds, including certain drugs, may possibly be administered via this route.</jats:p>