BACKGROUND: Although iron deficiency is known to interrupt vitamin A (VA) metabolism, the ability of iron repletion to restore VA metabolism and kinetics in iron-deficient rats is not well understood. OBJECTIVES: In the present study, we examined the effects of dietary iron repletion on VA status in rats with pre-existing iron deficiency. METHODS: Weanling Sprague-Dawley rats were fed a VA-marginal diet (0.35 mg retinol/kg diet) containing either a normal concentration of iron [35 ppm, control group (CN)] or reduced iron (3 ppm, iron-deficient group, ID-); after 5 wk, 4 rats/group were killed for baseline measurements. A 3H-labeled retinol emulsion was administered intravenously to the remaining rats (n = 6, CN; n = 10, ID-) as tracer to initiate the kinetic study. On day 21 after dosing, n = 5 ID- rats were switched to the CN diet, generating an iron-repletion group (ID+). Blood samples were collected at 34 time points ≤92 d after dose administration, when all rats were killed and iron and VA status were determined. RESULTS: At baseline, ID- rats had developed iron deficiency, with a reduced plasma VA concentration (0.67 compared with 1.20 μmol/L in ID- and CN rats, respectively; P < 0.01) and a tendency toward higher liver VA (265 compared with 187 nmol in ID- and CN rats, respectively; P = 0.10). On day 92, iron deficiency persisted in ID- rats, accompanied by 2-times higher liver VA (456 nmol compared with 190 nmol in ID- and CN rats, respectively; P < 0.001) but lower plasma VA (0.64 compared with 0.94 μmol/L in ID- and CN rats, respectively; P = 0.05). ID+ rats not only recovered from iron deficiency, but also exhibited less liver VA sequestration (276 nmol) and normal plasma VA (0.91 μmol/L, not different from CN rats). CONCLUSIONS: Our results suggest that iron repletion can remove the inhibitory effect of iron deficiency on hepatic mobilization of VA and restore plasma retinol concentrations in iron-deficient rats, setting the stage for kinetic studies of VA turnover in this setting.
BACKGROUND: Although iron deficiency is known to interrupt vitamin A (VA) metabolism, the ability of iron repletion to restore VA metabolism and kinetics in iron-deficient rats is not well understood. OBJECTIVES: In the present study, we examined the effects of dietary iron repletion on VA status in rats with pre-existing iron deficiency. METHODS: Weanling Sprague-Dawley rats were fed a VA-marginal diet (0.35 mg retinol/kg diet) containing either a normal concentration of iron [35 ppm, control group (CN)] or reduced iron (3 ppm, iron-deficient group, ID-); after 5 wk, 4 rats/group were killed for baseline measurements. A 3H-labeled retinol emulsion was administered intravenously to the remaining rats (n = 6, CN; n = 10, ID-) as tracer to initiate the kinetic study. On day 21 after dosing, n = 5 ID- rats were switched to the CN diet, generating an iron-repletion group (ID+). Blood samples were collected at 34 time points ≤92 d after dose administration, when all rats were killed and iron and VA status were determined. RESULTS: At baseline, ID- rats had developed iron deficiency, with a reduced plasma VA concentration (0.67 compared with 1.20 μmol/L in ID- and CN rats, respectively; P < 0.01) and a tendency toward higher liver VA (265 compared with 187 nmol in ID- and CN rats, respectively; P = 0.10). On day 92, iron deficiency persisted in ID- rats, accompanied by 2-times higher liver VA (456 nmol compared with 190 nmol in ID- and CN rats, respectively; P < 0.001) but lower plasma VA (0.64 compared with 0.94 μmol/L in ID- and CN rats, respectively; P = 0.05). ID+ rats not only recovered from iron deficiency, but also exhibited less liver VA sequestration (276 nmol) and normal plasma VA (0.91 μmol/L, not different from CN rats). CONCLUSIONS: Our results suggest that iron repletion can remove the inhibitory effect of iron deficiency on hepatic mobilization of VA and restore plasma retinol concentrations in iron-deficient rats, setting the stage for kinetic studies of VA turnover in this setting.
Keywords:
animal model; hyporetinolemia; interaction between iron and vitamin A; iron deficiency; iron repletion; micronutrients; retinol; vitamin A metabolism; vitamin A mobilization; vitamin A storage
Authors: F Ahmed; M R Khan; R Karim; S Taj; T Hyderi; M O Faruque; B M Margetts; A A Jackson Journal: Eur J Clin Nutr Date: 1996-06 Impact factor: 4.016
Authors: Hesham M Al-Mekhlafi; Ebtesam M Al-Zabedi; Mohamed T Al-Maktari; Wahib M Atroosh; Ahmed K Al-Delaimy; Norhayati Moktar; Atiya A Sallam; Wan Ariffin Abdullah; Rohana Jani; Johari Surin Journal: Nutrients Date: 2013-12-31 Impact factor: 5.717