Effect of exposure to lead on maturation of intestinal iron absorption of rats

Abstract

The influence of lead on iron absorption was investigated at various stages of development in rat pups exposed to lead first through mothers’ milk and later in their solid diet. Hematocrit, hemoglobin, iron absorption, and tissue iron concentration were measured on d 14, 20, 23, 29, 35, 42, and 63 after birth. Both hematocrit and hemoglobin in the lead‐exposed group were significantly below control levels at all periods earlier than d 42 and 63, respectively. Absorption of iron ([ ⁵⁹ Fe]‐ferrous citrate in 10 ^‐4 M FeSO ₄ ) from intestinal loops measured over ½ h remained at preweaning levels (10–12% of total activity added to the loop) for at least 1 wk after weaning in the lead‐exposed rats, whereas in control animals iron absorption fell to adult levels (3–4%) at weaning. Spleen weight was significantly elevated in lead‐exposed rats compared with control rats at all ages beyond d 14. However, spleen iron content (micrograms of Fe per gram of tissue) was not significantly elevated in the lead‐exposed group before d 42. The results indicate that exposure to lead does not reduce iron absorption from the intestinal tract; thus alteration of intestinal iron absorption does not contribute to lead‐induced anemia. Indeed, lead‐exposed rats demonstrated increased iron uptake.