Engler M M, Bellenger-Germain S H, Engler M B, Narce M M, Poisson J P
Laboratory of Cardiovascular Physiology, Department of Physiological Nursing, University of California, San Francisco 94143-0610, USA.
Lipids. 2000 Sep;35(9):1011-5. doi: 10.1007/s11745-000-0612-0.
Docosahexaenoic acid (DHA, 22:6n-3) is an n-3 polyunsaturated fatty acid which attenuates the development of hypertension in spontaneously hypertensive rats (SHR). The effects of DHA on delta-9-desaturase activity in hepatic microsomes and fatty acid composition were examined in young SHR. Two groups of SHR were fed either a DHA-enriched diet or a control diet for 6 wk. Desaturase activity and fatty acid composition were determined in hepatic microsomes following the dietary treatments. Delta-9-desaturase activity was decreased by 53% in DHA-fed SHR and was accompanied by an increase in 16:0 and a reduction in 16:1n-7 content in hepatic microsomes. The DHA diet also increased the levels of eicosapentaenoic acid (20:5n-3) and DHA. The n-6 fatty acid content was also affected in DHA-fed SHR as reflected by a decrease in gamma-linolenic acid (18:3n-6), arachidonic acid (20:4n-6), adrenic acid (22:4n-6), and docosapentaenoic acid (22:5n-6). A higher proportion of dihomo-gamma-linolenic acid (20:3n-6) and a lower proportion of 20:4n-6 is indicative of impaired delta-5-desaturase activity. The alterations in fatty acid composition and metabolism may contribute to the antihypertensive effect of DHA previously reported.
二十二碳六烯酸（DHA，22:6n-3）是一种n-3多不饱和脂肪酸，可减轻自发性高血压大鼠（SHR）高血压的发展。在幼年SHR中研究了DHA对肝微粒体中Δ9-去饱和酶活性和脂肪酸组成的影响。两组SHR分别喂食富含DHA的饮食或对照饮食6周。饮食处理后测定肝微粒体中的去饱和酶活性和脂肪酸组成。喂食DHA的SHR中，Δ9-去饱和酶活性降低了53%，同时肝微粒体中16:0增加，16:1n-7含量降低。DHA饮食还增加了二十碳五烯酸（20:5n-3）和DHA的水平。喂食DHA的SHR中的n-6脂肪酸含量也受到影响，表现为γ-亚麻酸（18:3n-6）、花生四烯酸（20:4n-6）、肾上腺酸（22:4n-6）和二十二碳五烯酸（22:5n-6）减少。二高-γ-亚麻酸（20:3n-6）比例较高而20:4n-6比例较低表明Δ5-去饱和酶活性受损。脂肪酸组成和代谢的改变可能有助于先前报道的DHA的降压作用。
