Effects of saturated fatty acids on n-6 fatty acid metabolism in cultured human monocyte-like cells (U937).
Effects of supplementation of saturated fatty acids (16:0 and 18:0) on metabolism of the cytotoxic n-6 fatty acids in cultured human monocyte-like cells (U937) have been examined. U937 cells were incubated in 5% delipidated fetal bovine serum containing 16:0 and 18:0. Supplementation of either 16:0 or 18:0 has no significant effect on the uptake of 18:2n-6 and 18:3n-6. However, addition of 16:0 to the medium increased whereas 18:0 suppressed the cytotoxic effects of 18:2n-6 and 18:3n-6. In addition, 16:0 supplementation reduced the incorporation of n-6 fatty acids in cellular phospholipid fraction, and enhanced the metabolism of n-6 fatty acids, particularly the conversion of 20:3n-6 to 20:4n-6 in U937 cells. Results with microsomes prepared from U937 cells also showed that 16:0 supplementation increased the delta 5 desaturase activity. This may be related in part to an increase in the availability of 20:3n-6, since results obtained in a separate study have shown that 16:0 competed with 20:3n-6 for incorporation into the phospholipid molecule at sn-2 position. Increasing the availability and formation of long chain n-6 fatty acids, which are cytotoxic, might also be responsible for increasing cytotoxicity of 16:0 supplementation.
Howie
A
A
Efamol Research Institute, Kentville, Nova Scotia, Canada.
Huang
Y S
YS
Rozee
L
L
Horrobin
D F
DF
D002470:Cell Survival; D002478:Cells, Cultured; D005227:Fatty Acids / Q000494:pharmacology*; D043371:Fatty Acids, Omega-6; D005231:Fatty Acids, Unsaturated / Q000378:metabolism*; D006801:Humans; D008861:Microsomes / Q000378:metabolism; D009000:Monocytes / Q000378:metabolism*
D005227:Fatty Acids; D043371:Fatty Acids, Omega-6; D005231:Fatty Acids, Unsaturated