Effect of dietary fatty acids on Δ5 desaturase activity and biosynthesis of arachidonic acid in rat liver microsomes

Lipids ◽  
1983 ◽  
Vol 18 (11) ◽  
pp. 781-788 ◽  
Author(s):  
I. N. T. De Gómez Dumm ◽  
M. J. T. De Alaniz ◽  
R. R. Brenner
Keyword(s):  
Fatty Acids ◽  
Arachidonic Acid ◽  
Rat Liver ◽  
Desaturase Activity ◽  
Liver Microsomes ◽  
Dietary Fatty Acids ◽  
Rat Liver Microsomes ◽  
Δ5 Desaturase

scholarly journals Effect of dietary fats on the δ6- and δ5-desaturation of fatty acids in rat liver microsomes

1983 ◽  
Vol 50 (3) ◽  
pp. 749-756 ◽  
Author(s):  
D. Kirstein ◽  
C.-E. Høy ◽  
G. Hølmer
Keyword(s):  
Arachidonic Acid ◽  
Linolenic Acid ◽  
Rat Liver ◽  
Desaturase Activity ◽  
Liver Microsomes ◽  
Dietary Fats ◽  
Rat Liver Microsomes ◽  
Δ5 Desaturase ◽  
Substrate Level

1. Rats were given diets containing (% dietary energy): 46 arachis oil (AO), 36 partially-hydrogenated arachis oil (HAO) + 10 AO, 36 partially-hydrogenated marine oil (HMO) + 10 AO, or 46 of a combination of rape-seed oils high and low in erucic acid (RSO + LERSO).2. In the liver microsomes the content of arachidonic acid (20:4ω6) was reduced inthe groups given HAO + AO and HMO + AO.3. The rates of Δ6-desaturation of linoleic acid into γ-linolenic acid (18:3ω6) and of Δ5-desaturation of dihomo-γ-linolenic acid into arachidonic acid were studied in vitro at two substrate levels: a high substrate level reflecting maximal microsomal desaturase activity in rat liver and a low substrate level reflecting desaturase activity under physiological conditions.4. Dietary HAO, rich in 18:1 isomers, suppressed the Δ6-desaturase activity butnot the Δ5-desaturase activity. Dietary HMO, rich in 18:1, 20:1 and 22:1 isomers, reduced both Δ6- and Δ5-desaturase activities.

Fluorescence polarization studies of rat liver microsomes with altered phospholipid desaturase activities

1980 ◽  
Vol 58 (10) ◽  
pp. 952-958 ◽  
Author(s):  
E. L. Pugh ◽  
M. Kates ◽  
A. G. Szabo
Keyword(s):  
Fatty Acid ◽  
Rat Liver ◽  
Fluorescence Polarization ◽  
Desaturase Activity ◽  
Liver Microsomes ◽  
Rat Liver Microsomes ◽  
Polarization Ratio ◽  
Parinaric Acid ◽  
Cis And Trans ◽  
Normal Controls

Phospholipid desaturase activity of rat liver microsomes can be varied by dietary manipulation: rats starved and refed a "fat-free" diet have two to three times the activity of normal controls whereas starved rats have no detectable activity. These changes were accompanied by changes in fatty acid composition of the microsomal phospholipids, resulting in a double bond:saturated fatty acid mole ratio (moles double bonds per mole saturated fatty acid) of 5.7 in control and starved rats and 4.7 in starved–refed rats. Fluorescence polarization ratio [Formula: see text] of cis- and trans-parinaric acid (PnA) showed no significant differences in physical state of the three microsomal preparations. However, the isolated microsomal phospholipids with trans-PnA as probe showed differences in the temperature at which onset of a change in polarization ratio occurred (starved–refed > normal > starved rats). With the cis-PnA as probe, the polarization ratio showed no change in the range 10–40 °C but was significantly higher (1.8) in starved–refed rats than in normal and starved rats (1.6 in both cases). These data indicate that the microsomal phospholipids of starved–refed animals were in a less fluid state than those from control and starved rats and that this decrease in fluidity was correlated with an increase in phospholipid desaturase activity.

Biosynthetic utilization of photoreactive fatty acids by rat liver microsomes

1984 ◽  
Vol 62 (6) ◽  
pp. 375-378 ◽  
Author(s):  
Pierre Leblanc ◽  
Gerhard E. Gerber
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Rat Liver ◽  
Alkyl Chain ◽  
Liver Microsomes ◽  
Rat Liver Microsomes ◽  
Phospholipid Synthesis ◽  
Derivatives Of

The photoreactive ω-diazirinophenoxy derivatives of nonanoate, undecanoate, tridecanoate, and pentadecanoate were shown to be activated by rat liver microsomes to the corresponding acyl-CoA derivatives. The Km and Vmax for these fatty acid analogues were determined; the values obtained indicate that the addition of a photoreactive group to an alkyl chain has an effect similar to that of elongation of the chain by about seven carbons. Incubation of microsomes in the presence of lysophospholipids resulted in the incorporation of the photoreactive fatty acids into the corresponding phospholipids. The ability of mammalian systems to utilize these photoreactive fatty acids for phospholipid synthesis establishes their suitability as photoaffinity analogues of fatty acids.

Sign in / Sign up

Export Citation Format

Share Document