Transfer of iron across the placenta and fetal membranes in the rat.

GLASSER, STANLEY R., CHARLES WRIGHT, AND ROBERT M. HIEYSSEL. Transfer of iron acrm the placenta and f&d membranes in the rat. Am. J. Physiol. 215(l) 2051-210. 1968.-The rate of accumulation and distribution of “gFe in the fetus, placenta, and accessory tissues was studied at different stages of gestation following iv injection of zgFe. There is a steady increase in percent of SgFe and in the total amount of iron transferred to the fetus through day 18 of gestation at which time an apparent plateau and decrease in iron transfer occurs. After day 16 the greatest portion of the jgFe cleared from the maternal circulation by each fetoplacental unit (FPU) is taken up by the fetus. The fetal liver accounts for the largest fraction of SgFe taken up by the fetus (days 14 and 16). Early in the fetal period (days I.2 and 14) placenta and yolk sac retain the major portion of the small amount of 5gFe cleared from the maternal circulation. Following removal of the fetus (fetectomy) after day 16, ‘igFe uptake by placenta was equal to or greater than that of the entire FPU and indicates that extraction of iron from the maternal circulation is a primary function of the placenta dissociable from and not dependent on a fetal acceptor.