Effect of magnesium deficiency on Δ6 desaturase activity and fatty acid composition of rat liver microsomes

Lipids ◽  
1989 ◽  
Vol 24 (8) ◽  
pp. 727-732 ◽  
Author(s):  
M. M. Mahfouz ◽  
F. A. Kummerow
Keyword(s):  
Fatty Acid Composition ◽  
Fatty Acid ◽  
Acid Composition ◽  
Rat Liver ◽  
Desaturase Activity ◽  
Magnesium Deficiency ◽  
Liver Microsomes ◽  
Rat Liver Microsomes ◽  
Δ6 Desaturase

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.

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