Mechanisms of heme iron absorption: Current questions and controversies

Figure 2 Results from Belgrade rats for heme iron absorption (A), sucrase activity (B) and lactase activity (C) over a series of experiments. Figures in brackets indicate n values, and data is mean ± SE. Groups marked with ‘a’ or ‘b’ are significantly different from the control group (1-way ANOVA ^aP < 0.05 and ^bP < 0.005, respectively). In early experiments 1 and 2, b/b and +/b rats had significantly lower heme iron absorption than Wi controls, initially suggesting a possible role for DMT1. However, sucrase and lactase activity was also lower in b/b and +/b rats indicating a more general defect in the mucosa of the Belgrade strain. In experiment 3, +/+ rats were used as an improved control to account for strain differences between Wi and Belgrade strains, but in this (and subsequent) experiments there was an apparent recovery in both heme iron absorption as well as sucrase and lactase activities. We could find no explanation for this dramatic phenotypic change, making it difficult to correlate DMT1 function with heme iron absorption.