EFFECTS OF DIETARY LINOLENATE ON ARACHIDONATE

建议的研究目的是评估饮食的疗效。 亚麻酸(18：3n-3)，与二十碳五烯酸(20：5n-3)或 鱼油中富含二十二碳六烯酸(22：6N-3)，可抑制 花生四烯酸(20：4n-6)在大鼠体内形成二十碳二烯 纸巾。20：5N-3在减量中的有益效果 血栓形成的可能性被认为主要是由于它的 竞争性抑制20：4N-6向血栓素A2的转化 (TXA2)，并通过置换降低血小板中20：4N-6水平。 一个重要的问题是，另一种饮食是否 N-3脂肪酸可以达到类似甚至更有益的效果 20：5N-3。本申请者建议饮食18：3n-3抑制 亚油酸(18：3N-6)转化为20：4N-6。它还抑制了 20：4N-6环氧合酶衍生产物的形成。此外， 18：3n-3不是白三烯(LT)的底物，而20：5n-3是 5-脂氧合酶形成并戊烯的首选底物 这就是。因此，饮食18：3n-3可能是一种比20：5n-3更有效的抑制剂。 3为LTS的生物合成。具体目的是将18：3n-3与 20：5n-3或22：6n-3对：(1)二十烷类前体水平的影响 游离脂肪酸组分和组织磷脂中的酸，以及(2) 组织中20：4n-6和20：5n-3来源的二十烷类化合物的形成。 分别以18：3n-3、20：5n-3或22：6n-3的纯化量饲喂大鼠 恒定量18：2N-6存在12周。二十烷类化合物 在组织中合成的将通过放射免疫分析和 免疫层析法。我们的长远目标是建立 我们饮食中n-3和n-6脂肪酸的理想比例可以减少某些 患冠心病的风险。目前，大多数饮食指南使用 不区分多不饱和脂肪酸类型的多不饱和脂肪酸 (n-3或n-6)。将来，此比率可能需要在 饮食指南。

The objective of the proposed study is to evaluate the efficacy of dietary linolenic acid (18:3n-3), as compared to eicosapentaenoic acid (20:5n-3) or docosahexaenoic acid (22:6n-3) which are abundant in fish oil, to inhibit the formation of eicosanoids derives from arachidonic acid (20:4n-6) in rat tissues. The suggested beneficial effects of 20:5n-3 in reducing thrombogenic potential are considered to be primarily due to its competitive inhibition of the conversion of 20:4n-6 to thromboxane A2 (TXA2), and reduction of the 20:4n-6 level in platelets by displacement. An important question can be raised as to whether another type of dietary n-3 fatty acid can achieve similar or even more beneficial effects than 20:5n-3. This applicant proposes that dietary 18:3n-3 inhibits the conversion of linoleic acid (18:3n-6) to 20:4n-6. It also inhibits the formation of cyclooxygenase-derived products of 20:4n-6. Furthermore, 18:3n-3 is not a substrate for leukotrienes (LT), whereas 20:5n-3 is a preferred substrate for 5-lipoxygenase leading to the formation of pentaene LTs. Thus, dietary 18:3n-3 may be a more effective inhibitor than 20:5n- 3 for the biosynthesis of LTs. The specific aim is to compare 18:3n-3 with 20:5n-3 or 22:6n-3 for its effects on: (1) levels of eicosanoid precursor acids in free fatty acid fractions and tissue phospholipids, and (2) the formation of eicosanoids derived both from 20:4n-6 and 20:5n-3 in tissues. Rats will be fed graded amounts of purified 18:3n-3, 20:5n-3 or 22:6n-3 in the presence of a constant amount of 18:2n-6 for 12 weeks. Eicosanoids synthesized in tissues will be determined by radioimmunoassay and immunochromatographic assay. The long term objective is to establish the desirable ratio of n-3 to n-6 fatty acids in our diets to reduce certain risks of coronary heart disease. Presently, most dietary guidelines use polyunsaturated fatty acids (PUFA) without differentiating types of PUFA (n-3 or n-6). In the future, this ratio may need to be specified in the dietary guidelines.