Submitted to: Recommended Dietary Allowances Workshop
Publication Type: Abstract Only
Publication Acceptance Date: September 10, 1995
Publication Date: N/A
Technical Abstract: Enterocyte cytosolic aconitase activity (cAcon) may be an index of iron regulatory protein activity and regulate iron (Fe) uptake and use. We examined the relations among cAcon, Fe status and absorption. Varied body Fe stores were produced by feeding weanling rats diets with Fe concentrations of 10 vs 35 ug/g for 4 wk. In Expt 1, rats were fed a low Fe-high safflower oil diet for 2 wk, followed by diets with low or high Fe for another 4 wk. Hb and cAcon change were less (p<0.001), 59**Fe absorption was greater (p<0.001), enterocyte cytosolic (CFe) and total cellular Fe (TCFe) were less (p<0.001) in rats fed low as compared to adequate Fe. In rats fed adequate Fe, TCFe depended (p<0.01, r**2=0.59) on liver and serum Fe. Significant (p less than or equal to 0.05) relations were observed between CFe and Hb (r**2=0.17), and cAcon and CFe (r**2=0.12) in rats fed adequate Fe. Effect of Fe repletion found that cAcon increased with improvements in Fe status. No relation was observed between cAcon and iron status (Hb). Other rats were fed diets containing 7 (FeD), 16 (FeMD) or 35 ug/g Fe (FeA) or pair-fed the Fe-adequate (FePFA) diet for 4 wk. Hb decreased (p<0.05) and total iron binding capacity (TIBC) increased (p<0.05) in FeD rats; FeMD rats had values intermediate between FeD and adequate (FeA and FePFA) rats. Transferrin saturation (Tfsat), serum, liver and CFe and TCFe were less (p<0.05) in FeD and FeMD than in FeA rats. cAcon tended to increase with improved Fe status and was related to Hb (p=0.005) and TIBC (p=0.03). TCFe depended on TIBC (p=0.003) and Tfsat (p=0.002); CFe depended on (TIBC, p=0.0001; Tfsat, p=0.003). CFe depended on Hb, serum and liver Fe (p=0.001). Fe status did not affect liver cAcon. Thus Fe status affects cAcon which may control Fe metabolism.