Perturbed Vitamin A Status Induced by Iron Deficiency Is Corrected by Iron Repletion in Rats with Pre-Existing Iron Deficiency

Abstract

<jats:title>ABSTRACT</jats:title> <jats:sec> <jats:title>Background</jats:title> <jats:p>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.</jats:p> </jats:sec> <jats:sec> <jats:title>Objectives</jats:title> <jats:p>In the present study, we examined the effects of dietary iron repletion on VA status in rats with pre-existing iron deficiency.</jats:p> </jats:sec> <jats:sec> <jats:title>Methods</jats:title> <jats:p>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.</jats:p> </jats:sec> <jats:sec> <jats:title>Results</jats:title> <jats:p>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 &amp;lt; 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 &amp;lt; 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).</jats:p> </jats:sec> <jats:sec> <jats:title>Conclusions</jats:title> <jats:p>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.</jats:p> </jats:sec>

Vitamin A deficiency regulates the expression of ferritin in young male Wistar rats

“…However, it is important to remark that dietary iron changes do not affect serum retinol amounts when dietary vitamin A levels are low or absent. Previous findings showed a lack of consensus about the unidirectional effect of iron supplementation on the nutritional status of vitamin A and differences between the results of animal models and humans [50].…”

Pregnancy and Lactation Alter Vitamin A Metabolism and Kinetics in Rats under Vitamin A-Adequate Dietary Conditions

“…Plasma and liver samples collected at euthanasia were analyzed using ultra-performance liquid chromatography (UPLC) to determine VA mass as previously described [ 28 ]. For each plasma sample, an aliquot of 100 µL was used; for liver, a weighed portion of ~0.05 g frozen sample was taken for analysis.…”