Mucosal uptake and whole-body retention of dietary manganese are not altered in beta2-microglobulin knockout mice.

To further examine the interrelationships between manganese and iron absorption, the mucosal uptake, initial rate of loss, whole-body retention, and tissue distribution of an orally administered 54Mn radiotracer were compared between normal and beta2-microglobulin knockout [beta2m(-/-)] mice. These mutant mice are commonly used as a model for the study of human hemochromatosis, a hereditary iron-overload disease. Initial uptake of 54Mn by the intestinal mucosa, the liver, and the brain was not different between the two strains. The mutant mice had much higher concentrations of nonheme and total iron in the liver, but hepatic manganese, copper, magnesium, and zinc concentrations were similar between the two strains. In summary, the mucosal uptake and whole-body retention of manganese and tissue manganese concentrations were not altered in beta2m(-/-) mice; this suggests that normal homeostasis of manganese is not affected by the altered HFE protein-beta2m complex in these mice.