期刊
BRITISH JOURNAL OF NUTRITION
卷 88, 期 4, 页码 355-363出版社
CAMBRIDGE UNIV PRESS
DOI: 10.1079/BJN2002662
关键词
alpha-linolenic acid; polyunsaturated fatty acids; metabolism
The capacity for conversion of alpha-linolenic acid (ALNA) to n-3 long-chain polyunsaturated fatty acids was investigated in young men. Emulsified [U-C-13]ALNA was administered orally with a mixed meal to six subjects consuming their habitual diet. Approximately 33 % of administered [C-13]ALNA was recovered as (CO2)-C-13 on breath over the first 24 h. [C-13]ALNA was mobilised from enterocytes primarily as chylomicron triacylglycerol (TAG), while [C-13]ALNA incorporation into plasma phosphatidylcholine (PC) occurred later, probably by the liver. The time scale of conversion of [C-13]ALNA to eicosapentaenoic acid (EPA) and docosapentaenoic acid (DPA) suggested that the liver was the principal site of ALNA desaturation and elongation, although there was some indication of EPA and DPA synthesis by enterocytes. [C-13]EPA and [C-13]DPA concentrations were greater in plasma PC than TAG, and were present in the circulation for up to 7 and 14 d, respectively. There was no apparent C-13 enrichment of docosahexaenoic acid (DHA) in plasma PC, TAG or non-esterified fatty acids at any time point measured up to 21 d. This pattern of C-13 n-3 fatty acid labelling suggests inhibition or restriction of DHA synthesis downstream of DPA. [C-13]ALNA, [C-13]EPA and [C-13]DPA were incorporated into erythrocyte PC, but not phosphatidylethanolamine, suggesting uptake of intact plasma PC molecules from lipoproteins into erythrocyte membranes. Since the capacity of adult males to convert ALNA to DHA was either very low or absent, uptake of pre-formed DHA from the diet may be critical for maintaining adequate membrane DHA concentrations in these individuals.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据