Alteration in membrane fluidity of rat liver microsomes and of liposomes by protoporphyrin and its anti-lipidperoxidative effect.
The effect of protoporphyrin (PP) on membrane fluidity was investigated by electron paramagnetic resonance spectroscopy using doxyl stearate spin probes in relation to the anti-lipidperoxidative effect of PP. PP decreased the membrane fluidity in rat liver microsomes at concentrations above 1 mM and also in phosphatidylcholine (PC)-cholesterol (Cho) (100:8, a molar basis) liposomes. The lipid peroxidation stimulated by Fe2+ and L-ascorbic acid in those membrane preparations was attenuated along with the decrease in membrane fluidity by PP. Similar results were also found in Cho-rich PC (100:30 to 100) liposomes having less fluidity. These results suggest that the decrease in the membrane fluidity caused by PP may be involved in the antioxidative action of PP.
Imai
K
K
Faculty of Pharmaceutical Sciences, Setsunan University, Hirakata, Osaka, Japan.
Aimoto
T
T
Shima
T
T
Nakashima
T
T
Sato
M
M
Kimura
R
R
D000818:Animals; D000975:Antioxidants / Q000494:pharmacology; D004578:Electron Spin Resonance Spectroscopy; D015227:Lipid Peroxidation / Q000187:drug effects*; D008081:Liposomes / Q000187:drug effects*; D008297:Male; D008560:Membrane Fluidity / Q000187:drug effects*; D008862:Microsomes, Liver / Q000187:drug effects*; D011524:Protoporphyrins / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D013113:Spin Labels
D000975:Antioxidants; D008081:Liposomes; D011524:Protoporphyrins; D013113:Spin Labels