Dietary docosahexaenoic acid affects stearic acid desaturation in spontaneously hypertensive rats.

M M Engler, S H Bellenger-Germain, M B Engler, M M Narce, J P Poisson

Laboratory of Cardiovascular Physiology, Department of Physiological Nursing, University of California, San Francisco 94143-0610, USA. marguerite.engler@nursing.ucsf.edu

Lipids 2000 Sep

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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.

Citation

M M Engler, S H Bellenger-Germain, M B Engler, M M Narce, J P Poisson. Dietary docosahexaenoic acid affects stearic acid desaturation in spontaneously hypertensive rats. Lipids. 2000 Sep;35(9):1011-5