Labeled acetate incorporation into lipids and lipid elimination after oral administration in rat liver and adipose tissue.

摘要

To investigate the incorporation of acetate into fatty acids and their turnover, the time courses for the incorporation of labeled acetate into lipids in the liver and epididymal adipose tissue (adipose tissue) after the oral administration to rats were examined for 10 d. The labeled acetate was abundantly incorporated into lipids, mainly into triacylglycerols (TAG) in the liver, reached a maximum at 2 h after the administration and then quickly decreased. In the adipose tissue, the incorporation of the acetate reached a maximum after 8 h and began to decrease slowly after 2 d. The acetate incorporation into the lipids was markedly lower in the liver, plasma and adipose tissue of rats fed the corn oil diet than in those fed the fat-free diet. However, the half-lives of esterified fatty acids were similar in both dietary groups. The half-lives of esterified C16:0 and C18:1 in the decreasing phase were 5.4 and 8.9 h, respectively, in the liver, and 4.3 and 5.6 d, in the adipose tissue. The time courses for incorporation into plasma lipids were parallel to those in the liver. Thus the fatty acids synthesized in the liver appeared to be transported to adipose tissues and to stay there longer. Moreover, it is remarkable that 30% of the acetate radioactivities administered were found after 2 h in the whole liver: 75% of the products from the acetate at the maximum were lipids and 61%, of the lipids, TAG. The major products from acetate in the liver were lipids.