title: Comparison of recovery of previously depressed hepatic delta 6 desaturase activity in adult and old rats.
abstract: The ability to recover hepatic delta 6 desaturase (delta 6D) activity with linoleic acid as substrate was compared in adult and old rats. Male rats fed a diet deficient in alpha-linolenic acid were used either at 6 or 21 months. From these two ages onward, animals were fed a diet containing 10% fish oil for 3 months to reduce delta 6D activity. After this period, some of the animals were killed. The other animals were returned to the original diet deficient in alpha-linolenic acid. Fatty acid composition in liver and brain and hepatic delta 6D activity were analysed 3 and 7 days after the change in diet. When rats were fed the diet containing 10% fish oil, delta 6D activity was lower than in those fed the diet deficient in alpha-linolenic acid. The liver fatty acid composition was altered with disappearance of 22:5 n-6 and a decrease in 18:2 n-6, 20:4 n-6 and 22:4 n-6 accompanied by an increase in 20:5 n-3, 22:5 n-3 and 22:6 n-3. When rats were re-fed the original diet, delta 6D activity returned after 3 days to its initial level in the 9-month-old rats; in 24-month-old animals, recuperation was incomplete. The level of 20:4 n-6 and 18:2 n-6 increased in the liver concurrently with a decrease in levels of 20:5 n-3, 22:5 n-3 and 22:6 n-3. In both age groups, the brain fatty acid profile remained unchanged 7 days after returning to the diet deficient in alpha-linolenic acid.
authors.affiliation: Laboratoire de Nutrition et de Sécurité Alimentaire, INRA, Jouy-en-Josas, France.
authors.forename: L
authors.initials: L
authors.lastname: Dinh
authors.forename: J M
authors.initials: JM
authors.lastname: Bourre
authors.forename: O
authors.initials: O
authors.lastname: Dumont
authors.forename: G
authors.initials: G
authors.lastname: Durand
mesh_terms: D000375:Aging / Q000378:metabolism*; D000818:Animals; D001921:Brain / Q000201:enzymology / Q000378:metabolism; D044943:Fatty Acid Desaturases / Q000378:metabolism*; D005227:Fatty Acids / Q000032:analysis / Q000378:metabolism; D005260:Female; D005395:Fish Oils / Q000494:pharmacology; D008041:Linoleic Acids / Q000378:metabolism; D008042:Linolenic Acids / Q000172:deficiency / Q000378:metabolism; D050602:Linoleoyl-CoA Desaturase; D050356:Lipid Metabolism; D008055:Lipids / Q000032:analysis / Q000737:chemistry; D008099:Liver / Q000737:chemistry / Q000201:enzymology* / Q000378:metabolism; D008297:Male; D051381:Rats; D017208:Rats, Wistar
chemical_list: D005227:Fatty Acids; D005395:Fish Oils; D008041:Linoleic Acids; D008042:Linolenic Acids; D008055:Lipids; D044943:Fatty Acid Desaturases; D050602:Linoleoyl-CoA Desaturase