INFLUENCE OF AGING ON VITAMIN-A TRANSPORT INTO THE LYMPHATIC CIRCULATION
INFLUENCE OF AGING ON VITAMIN-A TRANSPORT INTO THE LYMPHATIC CIRCULATION
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DOI：
10.1016/0531-5565(90)90010-y
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发表时间：
1990-01-01
影响因子：
3.9
通讯作者：
DADUFALZA, V
中科院分区：
文献类型：
--
作者：
HOLLANDER, D;DADUFALZA, V
维生素A是一种脂溶性必需微量营养素。由于老年人血清中维生素A水平升高，我们通过测量淋巴循环中维生素A的出现率作为肠道吸收的指标，测试了老年大鼠肠道对维生素A的吸收能力。我们将生理浓度为350 nM的维生素注入2至23月龄Sprague-Dawley大鼠组的近端空肠中。收集淋巴液6 h，测定维生素A放射性。24小时内的淋巴流率范围为16 . ±. 3.1 ml最大为21.5 ±. 2.4最年轻的动物中ml。维生素A在23个月龄时进入淋巴的量最高，达到7869 .+-。154 pmol/6 h，而6732 . ±. 2个月时为106 pmol/h（p < .01）。随着年龄的增长，维生素A的吸收增加，从2个月龄时的35.6%增加到23个月龄时的41.6%。由于维生素A在肝脏中的累积储存，这种吸收和淋巴出现的增加具有营养和代谢意义。增加淋巴外观的维生素可以解释其较高的吸收和血清水平在老年人。
Vitamin A is a lipid soluble essential dietary micronutrient. Because aging individuals have elevated serum levels of vitamin A, we tested the intestinal absorptive capacity of the vitamin in aging rats by measuring the appearance rate of vitamin A in the lymphatic circulation as a measure of intestinal absorption. We infused the vitamin in a physiological concentration of 350 nM into the proximal jejunum of groups of Sprague-Dawley rats 2 to 23 months of age. Lymph was collected for 6 h and vitamin A radioactivity was measured. Lymph flow rate over 24 h ranged from 16 .+-. 3.1 ml in the oldest to 21.5 .+-. 2.4 ml in the youngest animals. Vitamin A transport into lymph was highest at 23 months of age, reaching 7869 .+-. 154 pmol/6 h as compared to 6732 .+-. 106 pmol/h at 2 months (p < .01). The increase in vitamin A absorption with aging represented an increase from 35.6% of the infused vitamin at 2 months to 41.6% at 23 months of age. Because of the cumulative storage of vitamin A in the liver this increase in absorption and lymphatic appearance is of nutritional and metabolic significance. Increased lymphatic appearance of the vitamin could explain its higher absorption and serum levels in aging individuals.