Premium
Effects of dietary fish oil on human mammary carcinoma and on lipid‐metabolizing enzymes
Author(s) -
Borgeson Charlotte E.,
Pardini Lani,
Pardini Ronald S.,
Reitz Ronald C.
Publication year - 1989
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/bf02535165
Subject(s) - fish oil , biology , polyunsaturated fatty acid , clinical chemistry , corn oil , carnitine , lipidology , biochemistry , metabolism , lipid metabolism , microsome , fatty acid , enzyme , endocrinology , medicine , fish <actinopterygii> , fishery
The growth rate of a human mammary carcinoma, MX‐1, was significantly reduced in athymic “nude” mice fed fish oil. Tumors from the fish oil‐fed animals also showed a greater sensitivity to two anti‐neoplastic agents, mitomycin C and doxorubicin. Mitochondria were isolated from control livers, host livers and tumors from fish oil‐and corn oil‐fed animals, and increased levels of 20∶5n−3 and 22∶6n−3 were found in mitochondrial lipids in all three tissues from the fish oil‐fed animals. To investigate the effect of dietary n−3 fatty acids on lipid metabolism, the activity of the acyl‐CoA:carnitine acyltransferase and three acyl‐CoA desaturases were measured. Carnitine acyltransferase activity toward all four acyl‐CoA substrates tested was markedly increased in mitochondria from liver by feeding fish oil. In mitochondria from tumors, feeding fish oil resulted in an increased activity toward only 18∶3n−3. These data suggest that fish oil may induce an increase in the oxidation of fatty acids. The Δ 9 ‐desaturase activity was decreased in microsomes from liver and tumor from fish oil‐fed animals. However, both the Δ 6 and Δ 5 desaturases were increased in tumor and in control liver as a result of feeding fish oil. The Δ 5 desaturase was not altered in microsomes from the host animals. The effect of fish oil on the Δ 5 and Δ 6 desaturases may involve alterations to metabolism of specific polyunsaturated fatty acids especially in the tumor tissue.