Plasma retinol is a major determinant of vitamin A utilization in rats
Plasma retinol is a major determinant of vitamin A utilization in rats
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DOI：
10.1093/jn/128.10.1767
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发表时间：
1998-10-01
影响因子：
4.2
通讯作者：
Green, MH
中科院分区：
文献类型：
--
作者：
Kelley, SK;Green, MH
我们研究了维生素A摄入量、肝脏维生素A水平、血浆视黄醇浓度和维生素A的不可逆利用之间的关系。为了补充现有数据，我们首先使用基于模型的房室分析来确定雄性Sprague-Dawley大鼠的维生素A利用率和其他动力学参数，这些大鼠具有足够的肝脏维生素A储备（类似于9000 nmol），并喂食含有低水平维生素A的饮食。在给予大鼠[H-3]视黄醇标记的血浆后，监测血浆视黄醇动力学43天，这些大鼠消耗的维生素A类似于23（组1，n = 6）或类似于4.2（组2，n = 6）nmol/d。将血浆示踪剂与时间的关系数据和实验结束时示踪剂不可逆损失的数据拟合至三室模型，其中血浆视黄醇在两个动力学不同的血管外室中与维生素A交换。不可逆利用率（类似于41 nmol/d）与维生素A平衡的大鼠相似，表明当肝脏维生素A储备充足时，利用率不会降低以补偿低维生素A摄入量。然后使用多元线性回归分析将这些数据与先前收集的数据相关联（共62只大鼠）（4.2-49 nmol/d），血浆视黄醇浓度（1.4-2.5 μ mol/L）和肝脏维生素A水平（1.2- 11，000 nmol）对维生素A利用的影响（处置率，4.2-68 nmol/d），处理速率（nmol/d）= -0.720（nmol/d）+0.844（d（-1）），相关系数R-（adj）（2）= 0.93（血浆视黄醇; nmol）+0.00139（d（-1））（肝脏维生素A; nmol）+0.220（维生素A摄入量; nmol/d）]。血浆视黄醇占处置率变异的92%（肝脏维生素A为5%，维生素A摄入量为3%）。我们的结论是，血浆视黄醇是一个主要的决定因素，不可逆的利用维生素A的大鼠低至中等维生素A摄入量。
We studied relationships among vitamin A intake, liver levels of vitamin A, plasma retinol concentrations and the irreversible utilization of vitamin A. To supplement existing data, we first used model-based compartmental analysis to determine vitamin A utilization and other kinetic parameters in male Sprague-Dawley rats that had adequate liver vitamin A stores (similar to 9000 nmol) and were fed a diet containing low levels of vitamin A. Plasma retinol kinetics were monitored for 43 d after administration of [H-3]retinol-labeled plasma to rats consuming similar to 23 (Group 1, n = 6) or similar to 4.2 (Group 2, n = 6) nmol vitamin A/d. Data for plasma tracer vs. time and for tracer lost irreversibly by the end of the experiment, were fit to a three-compartment model in which plasma retinol exchanges with vitamin A in two kinetically distinct extravascular compartments. Irreversible utilization rates (similar to 41 nmol/d) were similar to those for rats that are in vitamin A balance, suggesting that, when liver vitamin A stores are adequate, utilization rate is not decreased to compensate for a low vitamin A intake. Multiple linear regression analysis was then used to relate these and previously collected data (total, 62 rats) on vitamin A intake (4.2-49 nmol/d), plasma retinol concentration (1.4-2.5 mu mol/L) and liver vitamin A level (1.2-11,000 nmol) to vitamin A utilization (disposal rate, 4.2-68 nmol/d), A significant relationship (R-(adj)(2) = 0.93) was found for the equation [disposal rate (nmol/d) = -0.720 (nmol/d) + 0.844 (d(-1)) (plasma retinol; nmol) + 0.00139 (d(-1)) (liver vitamin A; nmol) + 0.220 (vitamin A intake; nmol/d)]. Plasma retinol accounted for 92% of the variability in disposal rate (vs. 5% for liver vitamin A and 3% for vitamin A intake). We conclude that plasma retinol is a main determinant of the irreversible utilization of vitamin A in rats with low to moderate vitamin A intake.