Document Detail

1-14C-linoleic acid distribution in various tissue lipids of guinea pigs following an oral dose.
MedLine Citation:
PMID:  11337980     Owner:  NLM     Status:  MEDLINE    
A recent study on the metabolism of 1-14C-alpha-linolenic acid in the guinea pig revealed that the fur had the highest specific activity of all tissues examined, 48 h after dosing. The present study investigated the pattern of tissue lipid labeling following an oral dose of 1-14C-linoleic acid after the animals had been dosed for the same time as above. Guinea pigs were fed one of two diets with a constant linoleic acid content (18% total fatty acids) and a different content of alpha-linolenic acid (0.3 or 17.3%) from weaning for 3 wk and 1-14C-linoleic acid was given orally to each animal for 48 h prior to sacrifice. The most highly labeled tissues (dpm/mg of linoleic acid) were liver, followed by brain, lung and spleen, heart, kidney and adrenal and intestines, in both diet groups. The liver had almost a three-fold higher specific activity than skin and fur which was more extensively labeled than the adipose and carcass. Approximately two-thirds of the label in skin plus fur was found in the fur which, because of a low lipid mass, would indicate that the fur was highly labeled. All tissues derived from animals on the diet with the low alpha-linolenic acid level were significantly more labeled than the tissues from the animals on the high alpha-linolenic acid diet, by a factor of 1.5 to 3. The phospholipid fraction was the most highly labeled fraction in the liver, free fatty acids were the most labeled fraction in skin & fur, while triacyglycerols were the most labeled in the carcass and adipose tissue. In these tissues, more than 90% of the radioactivity was found in fatty acids with 2-double bonds in the tissue lipids. These data indicate that the majority of label found in guinea pig tissues 48 h after dosing was still associated with a fatty acid fraction with 2-double bonds, which suggests there was little metabolism of linoleic acid to more highly unsaturated fatty acids in this time frame. In this study, the labeling of guinea pig tissues with linoleic acid, 48 h after dosing, was quite different from the labeling with alpha-linolenic acid reported previously. The retention of the administered radioactivity from 14C-linoleic acid in the whole body lipids was 1.6 times higher in the group fed the low alpha-linolenic acid diet (diet contained a total of 1.8 g PUFA/100 g diet) compared with the group fed the high alpha-linolenic acid diet (diet contained 3.6 g PUFA/100 g diet). The lack of retention of 14C-labeled lipids in the whole body would be consistent with an increased rate of beta-oxidation of the labeled fatty acid on the diet rich in PUFA, a result supported by other studies using direct measurement of labeled carbon dioxide.
Z Fu; N M Attar-Bashi; A J Sinclair
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Lipids     Volume:  36     ISSN:  0024-4201     ISO Abbreviation:  Lipids     Publication Date:  2001 Mar 
Date Detail:
Created Date:  2001-05-07     Completed Date:  2001-09-13     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0060450     Medline TA:  Lipids     Country:  United States    
Other Details:
Languages:  eng     Pagination:  255-60     Citation Subset:  IM    
Department of Food Science, RMIT University, Melbourne, Victoria, 3001, Australia.
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MeSH Terms
Adrenal Glands / metabolism
Brain / metabolism
Carbon Radioisotopes
Dietary Fats, Unsaturated / administration & dosage*,  analysis,  pharmacokinetics*
Guinea Pigs
Hair / metabolism
Intestines / metabolism
Kidney / metabolism
Linoleic Acid / administration & dosage*,  analysis,  pharmacokinetics*
Liver / metabolism
Lung / metabolism
Myocardium / metabolism
Skin / metabolism
Spleen / metabolism
Tissue Distribution
alpha-Linolenic Acid / administration & dosage
Reg. No./Substance:
0/Carbon Radioisotopes; 0/Dietary Fats, Unsaturated; 2197-37-7/Linoleic Acid; 463-40-1/alpha-Linolenic Acid

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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