title: Effects of high erucic acid diet on sphingomyelin biosynthesis in rat lung microsomes.
abstract: The amount of fatty acids in free ceramides and sphingomyelins and the biosynthesis of sphingomyelins were measured in lung microsomes of rats fed either a stock diet or semisynthetic diets containing 15% by weight of sunflower oil or rapeseed oil (48% erucic acid). The rapeseed oil diet increased the amount of 24 : 1 in free ceramides and decreased that of 24 : 0 in both fractions as compared to the other reference diets. Incubations of lyophilized microsomes with [14C acyl] ceramides (16 : 0, 18 : 1 or 24 : 1) and [3H methyl] phosphatidylcholine showed that in the stock and the sunflower oil diet groups the conversion kinetics of the 18 : 1 and 24 : 1 ceramides into sphingomyelins were the same while that of the 16 : 0 ceramide showed a higher affinity for the enzymatic systems. The rapeseed oil diet enhanced the apparent kinetic constants of 24 : 1 ceramide conversion. Studies on the appearance of 3H radioactivity in sphingomyelin showed that phosphorylcholine transfer from phosphatidylcholine to a ceramide acceptor occurred during sphingomyelin biosynthesis in lung microsomes. This pathway was also influenced by the rapeseed oil diet.
mesh_terms: D000818:Animals; D001937:Brassica; D002518:Ceramides / Q000378:metabolism; D004041:Dietary Fats / Q000008:administration & dosage / Q000494:pharmacology*; D004883:Erucic Acids / Q000008:administration & dosage / Q000494:pharmacology*; D005231:Fatty Acids, Unsaturated / Q000378:metabolism / Q000494:pharmacology*; D007700:Kinetics; D008168:Lung / Q000378:metabolism* / Q000648:ultrastructure; D008297:Male; D008861:Microsomes / Q000378:metabolism*; D009821:Oils / Q000008:administration & dosage; D051381:Rats; D011919:Rats, Inbred Strains; D013109:Sphingomyelins / Q000096:biosynthesis*
chemical_list: D002518:Ceramides; D004041:Dietary Fats; D004883:Erucic Acids; D005231:Fatty Acids, Unsaturated; D009821:Oils; D013109:Sphingomyelins