RELATIONSHIP BETWEEN DUODENAL CYTOSOLIC ACONITASE ACTIVITY AND IRON STATUS IN THE MOUSE

Cytosolic aconitase activity was assayed in duodenal mucosa from mice subjected to a variety of manipulations known to modulate duodenal iro n status and duodenal iron absorption. No changes in cytosolic aconita se activity were observed 1 h after oral FeSO4 dosing or intramuscular desferrioxamine treatment. Three days of hypoxic exposure and two wee ks treatment with intramuscular iron dextran also had no effect on cyt osolic aconitase. Three weeks growth on an iron deficient diet signifi cantly reduced cytosolic aconitase activity. In no situation was there any evidence for significant amounts of inactive aconitase which coul d be activated in vitro with FeSO4/cysteine. These data suggest that d uodenal cytosolic aconitase is not sensitive to acute changes in mucos al iron levels and is generally much less sensitive to body iron statu s than is duodenal iron absorption, There is evidence that chronic iro n depletion reduces cytosolic aconitase to a relatively small degree b ut generally activity is maintained, consistent with an important meta bolic role for the enzyme.