title: [Dietary fatty acids and delta 5 desaturation by rat liver microsomes].
abstract: This paper reports a comparative study of the influence of dietary fats on the delta 5 desaturation of dihomo-gamma-linolenic acid (20:3 n-6) to arachidonic acid (20:4 n-6) using rat liver microsomes. The kinetic conditions needed to measure the specific activity of desaturation have been described. The rate of delta 5 desaturation was studied at two substrate levels. In a first series of experiments, the liver microsomes of animals maintained on a chow diet showed less desaturation activity than those of animals fed a fat-free diet. For longer periods of control (fat-free) diet time, the amount of 20:4 n-6 produced in vitro was depressed and the 20:3 n-9/20:4 n-6 ratio in total lipids was enhanced. In a second series of experiments, groups of rats were fed semi-synthetic diets which contained 5 or 10% of dietary fats with different percentages of linoleic acid (18:2 n-6), alpha-linolenic acid (18:3 n-3), oleic acid (18:1 n-9) or saturated fatty acids. Liver microsomal delta 5 desaturase activities that were generally depressed, when compared with control rats, were moderately affected by dietary fats, except with a diet containing saturated fatty acids or alpha-linolenic acid for which delta 5 desaturation was decreased. These observations are discussed in relation with the recent literature.
authors.forename: J P
authors.initials: JP
authors.lastname: Blond
authors.forename: P
authors.initials: P
authors.lastname: Ratieuville
authors.forename: J
authors.initials: J
authors.lastname: Bézard
mesh_terms: D015126:8,11,14-Eicosatrienoic Acid / Q000378:metabolism; D000818:Animals; D016718:Arachidonic Acid; D001095:Arachidonic Acids / Q000378:metabolism; D000090943:Delta-5 Fatty Acid Desaturase; D004041:Dietary Fats / Q000008:administration & dosage / Q000494:pharmacology*; D044943:Fatty Acid Desaturases / Q000378:metabolism*; D005227:Fatty Acids / Q000494:pharmacology*; D007700:Kinetics; D019787:Linoleic Acid; D008041:Linoleic Acids / Q000008:administration & dosage; D008042:Linolenic Acids / Q000008:administration & dosage; D008297:Male; D008862:Microsomes, Liver / Q000187:drug effects / Q000201:enzymology*; D019301:Oleic Acid; D009829:Oleic Acids / Q000008:administration & dosage; D051381:Rats; D011919:Rats, Inbred Strains; D017962:alpha-Linolenic Acid
chemical_list: D001095:Arachidonic Acids; D000090943:Delta-5 Fatty Acid Desaturase; D004041:Dietary Fats; D005227:Fatty Acids; D008041:Linoleic Acids; D008042:Linolenic Acids; D009829:Oleic Acids; D017962:alpha-Linolenic Acid; D016718:Arachidonic Acid; D019301:Oleic Acid; D019787:Linoleic Acid; D044943:Fatty Acid Desaturases; D015126:8,11,14-Eicosatrienoic Acid
vernacular_title: Acides gras alimentaires et delta 5 désaturation par les microsomes hépatiques de rat.