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Effect of increasing the level of ω‐3 fatty acids on rat skeletal muscle sarcoplasmic reticulum
Author(s) -
Stubbs C. D.,
Kisielewski A. E.
Publication year - 1990
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/bf02537164
Subject(s) - phosphatidylethanolamine , phosphatidylcholine , fish oil , corn oil , chemistry , docosahexaenoic acid , biochemistry , endoplasmic reticulum , clinical chemistry , food science , docosapentaenoic acid , polyunsaturated fatty acid , degree of unsaturation , eicosapentaenoic acid , membrane fluidity , fatty acid , phospholipid , biology , membrane , chromatography , fish <actinopterygii> , fishery
The effect of dietary supplementation with fish oil as compared to corn oil on the lipid dynamics and calcium ATPase activity of rat skeletal sarcoplasmic reticulum was examined. After four‐week supplementation with fish oil, the levels of eicosapentaenoic (20∶5ω3), docosapentaenoic (22∶5ω3) and docosahexaenoic (22∶6ω3) acids in the total lipids were 5.3, 5.5 and 28.1% of the total fatty acids, respectively. In contrast, with corn oil only 22∶6 was found (8.9%). The level of these fatty acids in phosphatidylethanolamine from the membranes of animals fed fish oil was 4.2 (20∶5), 5.4 (22∶5) and 49.1% (22∶6); and for phosphatidylcholine it was 5.4 (20∶5), 4.6 (22∶5) and 17.4% (22∶6). Again, in corn oil fed animals, only 22∶6 was found in appreciable amounts, namely 28.3% in phosphatidylethanolamine and 1.8% in phosphatidylcholine. The steady state fluorescence anisotropy of 1,6‐diphenyl‐1,3,5‐hexatriene (DPH) was used to assess lipid order and was found to be only slightly less for membranes from animals supplemented with fish oil (0.120) as compared to those supplemented with corn oil (0.124). The calcium ATPase was found to be unaffected by supplementation consistent with the observed modest changes in lipid order as well as with suggestions that the enzyme is relatively insensitive to the level of unsaturation. It could be argued that if large increases in fatty acyl polyunsaturation in mammalian cell membranes would lead to marked alterations in bulk membrane lipid motional properties, this may not be in the interest of preserving physiological function. The complex mixture of phospholipid molecular species present in natural membranes may buffer against this by a type of passive adaptation, without the expenditure of metabolic energy, thus providing a homeoviscous environment able to optimally support membrane protein function.