1. 59Fe absorption from the novel
iron compound,
ferric maltol, was studied in rats pretreated twice daily for two weeks with non-radioactive
ferric maltol in oral doses containing 7 mg elemental
iron. Tissue accumulation of 59Fe 2 h after administration of radioactive
ferric maltol into the stomach was significantly lower in
iron pretreated animals than in saline-treated controls. 2. 59Fe uptake from
ferric maltol into isolated fragments of ileum and of duodenum was of similar magnitude in control animals but in
iron-treated animals, duodenal uptake was significantly lower than that of the ileum. 3. Absorption of 59Fe was also investigated in anaesthetized rats after intestinal perfusion with saline (controls) or with 5 mM
chenodeoxycholate to render the intestines more permeable. 4. Changes in permeability of the small intestine were monitored by estimating the amount of [14C]-
mannitol absorbed and fluid secreted with reference to the non-absorbable [3H]-
inulin in the perfusate effluents. 5. Despite the increased permeability of the intestines after
bile salt treatment, there was little difference from control in the tissue accumulation of 59Fe from
ferric maltol 2 h after intraduodenal administration. However 59Fe absorption from
ferrous sulphate was significantly increased after
bile salt treatment. 6. Gel filtration profiles of plasma made 5 and 60 min after intraduodenal administration of [59Fe]-ferric [3H]-
maltol demonstrated that
metal and
ligand do not enter the circulation as the complex even when intestinal permeability is increased. 7. Uptake of 59Fe was investigated in isolated fragments of rat small intestine after saline or
bile salt perfusion. Although 59Fe uptake from
ferric maltol was somewhat greater in the
bile salt-treated intestinal fragments, saturable kinetics were still observed. By contrast, "Fe uptake from
ferrous sulphate: ascorbate was greatly enhanced by
bile salt pretreatment and a very large diffusional component of uptake was evident. 8. It is concluded that
iron uptake from
ferric maltol may well be under endogenous regulatory control even in damaged intestines, so it is unlikely that this novel
iron compound can bring about
iron overload when administered orally.