Fetal iron balance in the rat

Abstract

Maternal and fetal iron balance through pregnancy was examined in the rat. The 20th day was selected for detailed study because of the peak iron requirements at that time. The standard diet provided a borderline iron supply to the fetus due to the limited availability of its iron for absorption. When a more available form of iron was used, normal fetal development occurred over a range of dietary iron content from 16 to 2500 mg/kg. At a level of 5 to 8 mg/kg, there was attrition of placental tissues with frequent fetal death and resorption. When the iron-deficient pregnancy was sustained, both maternal and fetal iron deficiency were present. At progressively higher levels of dietary iron, feto-placental iron content was constant despite a progressive increase in maternal iron stores. Fetal iron supply appeared to be determined primarily by plasma iron concentration, and, at normal levels, about 25% of transferrin iron passing through the uterine vasculature, was removed by the intact placentas. Low levels of plasma iron resulted in damage to fetal tissues and reduced the capacity of placental tissues to take up iron. At high levels of plasma iron, plasma iron turnover initially increased 5-fold over basal levels in nonpregnant animals due to increased placental uptake. However, with continued hyperferremia, uptake was regulated so as to maintain fetal iron at a normal level. A comparison of these data with human iron requirements explained the occurrence of both maternal and fetal iron deficiency in the rat, but only maternal iron deficiency in the human.

Expression of ferritin receptor in placental microvilli membrane in pregnant women with different iron status at mid-term gestation

“…However, it is possibly associated with severe iron de®ciency itself. It has been reported (Finch et al, 1983) that low levels of plasma iron, as found in severe iron de®ciency, could result in damage to fetal tissues and reduced capacity of placental tissues to take up iron. Singla et al (1996) demonstrated that a mild degree of maternal anemia has little in¯uence on iron accretion in the fetus.…”

Iron Deficiency in the Rat: Effects on Neutrophil Activation and Metabolism

“…After 6 wk on this diet, hemoglobin concentrations were determined and studies were performed only on rats with hemoglobin concentrations of less than 7 g/100 ml blood. Previously, we have shown that the low hemoglobin concentrations found in rats fed the low iron diet were accompanied by greatly lowered levels of plasma iron and increased total iron binding capacity and that the anemia was of a microcytic type (5,6,16). The control groups were fed the low iron diet during the experimental period, but received weekly intraperitoneal injections of 5 mg of iron in the form of iron dextran (Imferon, Merrell-National Labs).…”

Iron Deficiency in the Rat: Effects of Oxidative Metabolism in Distinct Types of Skeletal Muscle

“…After 6 wk on this diet, hemoglobin concentrations were determined and studies performed only on rats with hemoglobin concentrations of less than 7 g/100 ml blood. Previously, we have shown that the low hemoglobin concentrations found in rats fed the low iron diet were accompanied by greatly lowered levels of plasma iron and increased total iron binding capacity and that the anemia was of a microcytic type (4,5,14). The control groups were fed the low iron diet during the experimental period, but received weekly intraperitoneal injections of 5 mg of iron in the form of iron dextran (Imferon, MerrellNational Labs).…”