title: Selective reduction of delta 6 and delta 5 desaturase activities but not delta 9 desaturase in micropigs chronically fed ethanol.
abstract: This study investigated the mechanism by which chronic ethanol feeding reduces arachidonate and other highly unsaturated fatty acids in pig liver phospholipids. Five micropigs were fed a diet providing 89 kcal/kg body wt for 12 mo, with ethanol and fat as 40 and 34% of energy, respectively. Five control pigs were pairfed corn starch instead of ethanol. The activities of delta 6 and delta 5 desaturases (expressed as microsomal conversion of precursor to product) in liver from ethanol-fed pigs were reduced to less than half that of controls, whereas the activity of delta 9 desaturase was unaffected in the ethanol group. delta 5 Desaturase activity showed positive correlation with the abundance of its products in liver total phospholipids and microsomes in the ethanol group, but not in the controls. Correlation between delta 6 desaturase activity and its products showed similar pattern to that of delta 5 desaturase, but did not reach statistical significance. No difference was observed between the two groups in coenzyme A concentration in the liver. These results suggest that the selective reduction of delta 6 and delta 5 desaturase activities, not the microsomal electron transport system, are directly responsible for the altered profile of liver phospholipids.
authors.affiliation: Division of Clinical Nutrition and Metabolism, School of Medicine, University of California, Davis 95616.
authors.forename: M T
authors.initials: MT
authors.lastname: Nakamura
authors.forename: A B
authors.initials: AB
authors.lastname: Tang
authors.forename: J
authors.initials: J
authors.lastname: Villanueva
authors.forename: C H
authors.initials: CH
authors.lastname: Halsted
authors.forename: S D
authors.initials: SD
authors.lastname: Phinney
mesh_terms: D000437:Alcoholism / Q000201:enzymology*; D000818:Animals; D000090943:Delta-5 Fatty Acid Desaturase; D004032:Diet; D004041:Dietary Fats; D044943:Fatty Acid Desaturases / Q000378:metabolism*; D050602:Linoleoyl-CoA Desaturase; D008297:Male; D008862:Microsomes, Liver / Q000201:enzymology*; D008930:Mitochondria, Liver / Q000201:enzymology*; D009919:Orchiectomy; D010743:Phospholipids / Q000378:metabolism; D012016:Reference Values; D013552:Swine; D013556:Swine, Miniature
chemical_list: D000090943:Delta-5 Fatty Acid Desaturase; D004041:Dietary Fats; D010743:Phospholipids; D044943:Fatty Acid Desaturases; D050602:Linoleoyl-CoA Desaturase