Jang J T, Green J B, Beard J L, Green M H
Nutrition Department, The Pennsylvania State University, University Park, PA 16802, USA.
J Nutr. 2000 May;130(5):1291-6. doi: 10.1093/jn/130.5.1291.
In view of evidence that nutritional status of iron and vitamin A may affect the other nutrient's metabolism, we used model-based compartmental analysis to examine effects of iron deficiency on whole-body vitamin A dynamics in rats. Weanling male Sprague-Dawley rats were fed the AIN93G diet with 2.5 nmol retinyl palmitate/g and either 45 [control (CN)] or 4 microg/g Fe [iron-deficient (ID)] for 8 wk. ID rats consumed food ad libitum; CN rats were food-restricted so that their body weights were the same as ID rats. Two rats/group were killed; liver vitamin A was determined and used for vitamin A balance calculations. [(3)H]Retinol-labeled plasma was administered intravenously to remaining rats, and 27 serial blood samples were collected for 7 wk. At killing, plasma vitamin A was 0.52+/-0.12 (ID, n = 5) vs. 1.34+/-0.12 micromol/L (CN, n = 6; P<0.001), and liver vitamin A was 809+/-94 (ID) vs. 112+/-24 nmol (CN, P<0.001). Plasma tracer data were fit to a three- or four-compartment model using the Simulation, Analysis and Modeling computer program and kinetic parameters were calculated. Vitamin A transfer rate between the retinyl ester storage pool [14+/-3 (ID) vs. 24+/-4 nmol/d (CN), P<0.05] and plasma was lower in ID rats. Vitamin A remained longer in the body [44+/-11 (ID) vs. 22+/-3 d (CN), P<0.05]. Adjusted mean disposal rate was lower in ID (10.0) than CN rats (19.9 nmol/d), as was estimated vitamin A absorption efficiency [58% (ID) vs. 76% (CN)]. Our results suggest that iron deficiency inhibits mobilization of vitamin A stores and may decrease the absorption and irreversible utilization of vitamin A.
鉴于有证据表明铁和维生素A的营养状况可能会影响另一种营养素的代谢，我们采用基于模型的房室分析来研究缺铁对大鼠全身维生素A动态变化的影响。将断乳雄性Sprague-Dawley大鼠喂食AIN93G饲料，其中每克含有2.5 nmol棕榈酸视黄酯，铁含量分别为45 μg/g[对照组(CN)]或4 μg/g[缺铁组(ID)]，持续8周。缺铁组大鼠随意进食；对照组大鼠则限制进食量，使其体重与缺铁组大鼠相同。每组处死2只大鼠；测定肝脏维生素A含量并用于维生素A平衡计算。给其余大鼠静脉注射[³H]视黄醇标记的血浆，并在7周内采集27份连续血样。处死时，血浆维生素A含量为0.52±0.12（缺铁组，n = 5），而对照组（n = 6）为1.34±0.12 μmol/L（P<0.001），肝脏维生素A含量为809±94（缺铁组），而对照组为112±24 nmol（P<0.001）。使用模拟、分析和建模计算机程序将血浆示踪剂数据拟合到三室或四室模型，并计算动力学参数。缺铁组大鼠中，视黄酯储存池与血浆之间的维生素A转移率较低[14±3（缺铁组）对24±4 nmol/d（对照组），P<0.05]。维生素A在体内停留的时间更长[44±11（缺铁组）对22±3天（对照组），P<0.05]。缺铁组大鼠的调整后平均处置率[10.0]低于对照组大鼠（19.9 nmol/d），估计的维生素A吸收效率也是如此[58%（缺铁组）对76%（对照组）]。我们的结果表明，缺铁会抑制维生素A储存的动员，并可能降低维生素A的吸收和不可逆利用率。
