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Effect of dietary fats on desaturase activities and the biosynthesis of fatty acids in rat‐liver microsomes
Author(s) -
Mahfouz M. M.,
Smith T. L.,
Kummerow F. A.
Publication year - 1984
Publication title -
lipids
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.601
H-Index - 120
eISSN - 1558-9307
pISSN - 0024-4201
DOI - 10.1007/bf02534800
Subject(s) - microsome , oleic acid , chemistry , metabolism , biochemistry , food science , arachidonic acid , soybean oil , corn oil , fatty acid , lipidology , biosynthesis , enzyme
Four groups of rats were fed diets containing 15% (w/w) high‐oleic safflower oil (SFO, rich in cis ‐18∶1 acids), a mixture of 80% partially hydrogenated soybean oil plus 20% corn oil (H+CO, rich in trans ‐18∶1 acids), lard (L, rich in saturated fatty acids) and corn oil (Co, rich in 18∶2ω6). Fatty acid composition of liver microsomes and activities of the Δ 5 , Δ 6 and Δ 9 desaturases were determined. Microsomal Δ 6 desaturase activity and arachidonic acid were lower in the H+CO group compared with SFO of L. No difference was found in the Δ 5 or Δ 6 desaturase activity of CO and SFO groups. Thus, the oleic‐acid level of the SFO diet had no effect on the metabolism of 18∶2ω6. Fluorescent polarization studies, using trans ‐parinaric acid as a probe, showed no differences between the physical states of phospholipid vesicles made from lipids isolated from each group. We concluded that the trans ‐18∶1 acids in partially hydrogenated soybean oil have a more inhibitory effect than saturated acids on EFA metabolism, even in the presence of adequate amounts of essential fatty acid.