title: Dietary docosahexaenoic acid affects stearic acid desaturation in spontaneously hypertensive rats.
abstract: 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.
authors.affiliation: Laboratory of Cardiovascular Physiology, Department of Physiological Nursing, University of California, San Francisco 94143-0610, USA. marguerite.engler@nursing.ucsf.edu
authors.forename: M M
authors.initials: MM
authors.lastname: Engler
authors.forename: S H
authors.initials: SH
authors.lastname: Bellenger-Germain
authors.forename: M B
authors.initials: MB
authors.lastname: Engler
authors.forename: M M
authors.initials: MM
authors.lastname: Narce
authors.forename: J P
authors.initials: JP
authors.lastname: Poisson
mesh_terms: D000818:Animals; D004032:Diet; D004281:Docosahexaenoic Acids / Q000008:administration & dosage / Q000032:analysis / Q000494:pharmacology*; D005227:Fatty Acids / Q000032:analysis; D008297:Male; D008862:Microsomes, Liver / Q000737:chemistry / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism*; D051381:Rats; D011918:Rats, Inbred SHR; D013229:Stearic Acids / Q000737:chemistry / Q000378:metabolism*; D013230:Stearoyl-CoA Desaturase / Q000378:metabolism*
chemical_list: D005227:Fatty Acids; D013229:Stearic Acids; D004281:Docosahexaenoic Acids; C031183:stearic acid; D013230:Stearoyl-CoA Desaturase