Iron metabolism and placental transfer of iron in the term rhesus monkey (Macaca mulatta): a compartmental analysis.

The kinetics of iron and the transplacental iron transport in the near-term rhesus monkey were investigated by means of injection of 59Fe(III) bound to rhesus monkey transferrin into the maternal or into the fetal circulation. The experimentally obtained 59Fe(III) bound to rhesus monkey transferrin into the maternal or into the fetal circulation. The experimentally obtained 59Fe dissappearance and appearance curves were analyzed. The analyses were based on a 5-compartmental system. Alternative models were considered but found to be inadequate. Very high maternal as well as fetal iron turnover were calculated. The daily reflux of iron in the mother and in the fetus amounted to 75% of the amount of iron cleared from the plasma compartment daily. The calculated iron transport from mother to fetus was about 1.0 mumol/day/100 g fetus. The reverse transplacental iron transport was negligible. A small placental iron pool of exchangeable iron had to be assumed. There were no clear difference in the distribution of 59Fe over the fetal organs when the tracer dose was injected into the maternal or into the fetal circulation. Only one of the experiments showed a preferential labeling of the fetal liver when the label was given to the mother, a preference which would be expected on the basis of the hypothesis of Fletcher and Suter (1969).