Iron retention and distribution in the cadmium-induced iron deficiency

The retention and distribution of iron-59 after oral administration of a single iron dose in the presence and absence of various cadmium doses were tested in normal rats acutely or subchronically treated with various amounts of dietary cadmium (28, 56, 112 ppm). In a second series of experiments the kinetic parameters (Km and Vmax) of iron absorption were estimated in normal and iron-deficient rats after oral administration and from tied-off jejunal and duodenal segments. In acute experiments the retention of iron decreased inversely with respect to the cadmium dose administered simultaneously. After subchronic exposure to dietary cadmium for 4 weeks the retention of iron was increased if iron was administered alone or together with cadmium in comparison to normal controls. If iron was administered alone to subchronically treated animals, iron retention was of the same order of magnitude as in iron-deficient controls. However, if iron was administered together with cadmium (molar ratios 1/0.5, 1/1, 1/2 mumol/kg body wt) the retention of iron was decreased in a dose-dependent manner. The iron content in the liver and spleen of acutely exposed rats decreased, whereas the tissue content of the treated rats increased according to the increased body retention of iron. The utilization of iron for hemoglobin synthesis remained unchanged in all groups investigated.