Dietary n-3 fatty acids influence the lipid composition and physical properties of liver microsomal membranes in diabetic rats.
We examined the effect of n-3 fatty acid consumption on the lipid composition and physical properties of liver microsomal membranes in normal and experimental diabetic rats. Lipid analysis showed a significant increase in the cholesterol:phospholipid ratio in membranes of normal animals fed n-3 fatty acids as well as in both groups of diabetic rats. These changes would be in part responsible for the higher fluorescent polarization of DPH (1,6-diphenyl-1,3,5 hexatriene) observed in the diabetic groups compared with the normal ones. These alterations were partially compensated by an increase in the amount of phosphatidylcholine in the diabetic rats fed on n-3 fatty acids. However, proteins also play a role in determining the physical properties of the liver microsomes because in the liposomes derived from them, the fluorescent polarization of DPH decreased in the diabetics fed n-3 fatty acids. Measurements of fluorescence anisotropy of n-AS (2-, 7 and 12 (9 anthroyloxy) stearic acid) probes revealed a restricted rotational mobility in the middle zone of the bilayer. Consistently with this finding there was an elevation in the calculated unsaturation density of the fatty acids at the carbon 8 position. These experiments confirm the lipid abnormalities that take place in experimental diabetes and they show further that n-3 fatty-acid administration causes certain compensatory, and thus beneficial, changes in these abnormalities.
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Instituto de Investigaciones Bioquimicas de La Plata (INIBIOLP), Universidad Nacional de La Plata, Facultad de Ciencias Médicas, Argentina.
de Gómez Dumm
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D000818:Animals; D055592:Biophysical Phenomena; D001703:Biophysics; D003921:Diabetes Mellitus, Experimental / Q000378:metabolism*; D015525:Fatty Acids, Omega-3 / Q000008:administration & dosage* / Q000378:metabolism; D005454:Fluorescence Polarization; D007425:Intracellular Membranes / Q000737:chemistry / Q000378:metabolism; D050356:Lipid Metabolism; D008055:Lipids / Q000737:chemistry; D008297:Male; D008862:Microsomes, Liver / Q000737:chemistry / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar
D015525:Fatty Acids, Omega-3; D008055:Lipids