The effect of chemical hepatocarcinogenesis on liver phospholipid composition in rats fed N-6 and N-3 fatty acid-supplemented diets.
The effect of dietary fats on essential fatty acid metabolism in rats subjected to chemically induced hepatocarcinogenesis was studied. Sixty male rats were fed a diet supplemented with one of the following three oil compositions: 10% hydrogenated coconut oil (HCO); 5% hydrogenated coconut oil and 5% gamma-linolenic acid (18:3n-6)-rich evening primrose oil (EPO); or 5% hydrogenated coconut oil and 5% marine oil (FO). Half of the animals in each dietary regimen were subjected to hepatocarcinogenesis induction using diethylnitrosamine and 2-acetylaminofluorene (2-AAF) followed by partial hepatectomy, whereas the other half underwent hepatectomy without receiving diethylnitrosamine and 2-acetylaminofluorene. Liver phospholipid composition was analyzed. In comparison to the HCO group, the EPO group showed raised levels of arachidonic acid (20:4n-6) and suppressed n-3 fatty acids. The FO group, on the other hand, showed suppressed levels of n-6 and increased n-3 fatty acids. Hepatocarcinogenesis suppressed the level of 20:4n-6 and this effect was greater in the FO rats. The levels of dihomo-gamma-linolenic acid (20:3n-6) were increased by the hepatocarcinogenic treatment, and this effect was further accentuated in the EPO rats. These results suggest that hepatocarcinogenesis may suppress the activity of delta-5-desaturase, which may be one of the reasons why tumor cell membranes have low levels of long chain fatty acids, especially 20:4n-6 cells, and have an impaired capacity to undergo lipid peroxidation.
Nassar
B A
BA
Department of Pathology, Victoria General Hospital, Halifax, Nova Scotia, Canada.
Das
U N
UN
Huang
Y S
YS
Ells
G
G
Horrobin
D F
DF
D000818:Animals; D000074263:Coconut Oil; D004042:Dietary Fats, Unsaturated / Q000494:pharmacology*; D044943:Fatty Acid Desaturases / Q000032:analysis; D005228:Fatty Acids, Essential / Q000494:pharmacology; D005231:Fatty Acids, Unsaturated / Q000494:pharmacology*; D008041:Linoleic Acids; D008099:Liver / Q000737:chemistry*; D008114:Liver Neoplasms, Experimental / Q000139:chemically induced / Q000378:metabolism*; D008297:Male; D031665:Oenothera biennis; D010743:Phospholipids / Q000032:analysis*; D010938:Plant Oils / Q000494:pharmacology; D051381:Rats; D011916:Rats, Inbred F344; D017965:gamma-Linolenic Acid
D004042:Dietary Fats, Unsaturated; D005228:Fatty Acids, Essential; D005231:Fatty Acids, Unsaturated; D008041:Linoleic Acids; D010743:Phospholipids; D010938:Plant Oils; C028498:evening primrose oil; D017965:gamma-Linolenic Acid; D044943:Fatty Acid Desaturases; D000074263:Coconut Oil