FOLIC-ACID, 5-METHYL-TETRAHYDROFOLATE AND 5-FORMYL-TETRAHYDROFOLATE EXHIBIT EQUIVALENT INTESTINAL-ABSORPTION, METABOLISM AND INVIVO KINETICS IN RATS
FOLIC-ACID, 5-METHYL-TETRAHYDROFOLATE AND 5-FORMYL-TETRAHYDROFOLATE EXHIBIT EQUIVALENT INTESTINAL-ABSORPTION, METABOLISM AND INVIVO KINETICS IN RATS
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DOI：
10.1093/jn/122.9.1847
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发表时间：
1992-09-01
影响因子：
4.2
通讯作者：
GREGORY, JF
中科院分区：
文献类型：
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作者：
BHANDARI, SD;GREGORY, JF
研究了（6S）-[H-3]-5-甲基-四氢叶酸（5-甲基-H-4叶酸）、（6S）-[H-3]-5-甲酰-H-4叶酸和[H-3]叶酸在大鼠体内的肠吸收和体内动力学，以确定这些叶酸在大鼠体内的总体生物利用度是否存在内在差异。成年大鼠（每组n = 9）胃内给予适当剂量的叶酸（50 pmol/100 g体重）的50 mmol/L抗坏血酸盐（pH 7）。每种化合物在8小时内几乎完全吸收，并且与施用的叶酸形式有关的排泄动力学没有显著差异。在随后的8天内观察到双相排泄模式。尿液和粪便是重要的排泄途径。总同位素排泄（尿和粪）的快速期半衰期（t1/2）为0.11-0.12 d，而缓慢期的t1/2为13.4-15.9 d。无论给药形式如何，尿液和组织中标记叶酸的同位素分布和模式相似。这些结果表明，在本研究条件下，大鼠口服叶酸、5-甲基-H-4叶酸和5-甲酰-H-4叶酸的生物利用度相当。
The intestinal absorption and in vivo kinetics of (6S)-[H-3]-5-methyl-tetrahydrofolate (5-methyl-H-4folate), (6S)-[H-3]-5-formyl-H-4folate and [H-3]folic acid were investigated to determine whether inherent differences exist in the overall bioavailability of these folates in rats. Adult rats (n = 9 per group) were given an intragastric dose of the appropriate folate (50 pmol/100 g body wt) in 50 mmol/L ascorbate (pH 7). Each compound underwent nearly complete absorption within 8 h, and there was no significant difference in the excretion kinetics in relation to the form of folate administered. A biphasic pattern of excretion was observed over the following 8 d. Both urine and feces were important excretory routes. The rapid phase of total isotopic excretion (urinary and fecal) exhibited a half time (t1/2) of 0.11-0.12 d, whereas the t1/2 of the slower phase was 13.4-15.9 d. isotopic distributions and the pattern of labeled folates in urine and tissues were similar regardless of the form administered. These results indicate that the bioavailability of orally administered folic acid, 5-methyl-H-4folate and 5-formyl-H-4folate is equivalent in rats under the conditions of this study.