MUCOSAL IRON IN THE CONTROL OF IRON-ABSORPTION IN A RAT INTESTINAL TRANSPLANT MODEL

Isogeneic intestinal transplantation of iron-loaded and iron-deficient intestine into iron-deficient rats was performed in 20 Lewis rats to isolate the effect of intestinal mucosal iron on iron absorption. Rats were iron loaded with three weekly IM injections of 50 mg of iron dextran and were rendered iron deficient with an iron-deficient diet for 3 weeks. Iron status was assessed by hepatic and gut mucosal iron determination. Uptake and transfer of 59Fe-ascorbate was measured in an isolated perfused segment of transplanted intestine 48 hours after transplantation. The mean rate of uptake of 59Fe from an iron-loaded intestine (mean mucosal iron concentration, 7.97 ± 2.02 μmol/g) was 431 ± 27 nmol/30 min, and from an iron-deficient intestine (mean mucosal iron concentration, 1.35 ± 84 μmol/g), 743 ± 222 nmol/30 min (P < 0.001). The mean transfer of 59Fe from the mucosal cell to the body through an iron-loaded intestine was 63 ± 22 nmol/30 min, and through an iron-deficient intestine was 86 ± 32 nmol/30 min (P < 0.05). These results suggest that the gut mucosal iron concentration regulates the uptake and transfer of iron in the intestine. © 1991.