Eicosapentaenoic and docosapentaenoic acids are the principal products of α-linolenic acid metabolism in young men
Eicosapentaenoic and docosapentaenoic acids are the principal products of α-linolenic acid metabolism in young men
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DOI：
10.1079/bjn2002662
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发表时间：
2002-10-01
影响因子：
3.6
通讯作者：
Wootton, SA
中科院分区：
文献类型：
--
作者：
Burdge, GC;Jones, AE;Wootton, SA
在年轻男性中研究了α-亚麻酸（ALNA）转化为n-3长链多不饱和脂肪酸的能力。乳化[U-C-13]ALNA与混合餐一起口服给药，6例受试者食用其习惯饮食。在前24小时内，约33%的给药[C-13]ALNA在呼吸中以（CO2）-C-13形式回收。[C-13]ALNA主要以乳糜微粒三酰甘油（TAG）的形式从肠上皮细胞中动员，而[C-13]ALNA掺入血浆磷脂酰胆碱（PC）的时间较晚，可能是通过肝脏。[C-13]ALNA转化为二十碳五烯酸（EPA）和二十二碳五烯酸（DPA）的时间尺度表明，肝脏是ALNA去饱和和延长的主要部位，尽管有一些迹象表明肠细胞合成EPA和DPA。血浆PC中[C-13]EPA和[C-13]DPA浓度高于TAG，并且分别在循环中存在长达7天和14天。有没有明显的C-13富集二十二碳六烯酸（DHA）在血浆PC，TAG或非酯化脂肪酸在任何时间点测量到21天。C-13 n-3脂肪酸标记的这种模式表明DPA下游DHA合成的抑制或限制。[C-13]ALNA、[C-13]EPA和[C-13]DPA掺入红细胞PC，但不掺入磷脂酰乙醇胺，表明红细胞膜从脂蛋白中摄取完整的血浆PC分子。由于成年男性将ALNA转化为DHA的能力非常低或不存在，因此从饮食中摄取预先形成的DHA对于维持这些个体中足够的膜DHA浓度可能是至关重要的。
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.