Effects of age and dietary essential fatty acids on desaturase activities and on fatty acid composition of liver microsomal phospholipids of adult rats.
The combined effects of age and dietary n-6 and n-3 fatty acids were studied in 3-, 6- and 9-month-old rats. At each age, two groups were fed diets containing 5% (w/w) of vegetable oils rich in either 18:3n-6 (borage group) or 18:3n-6 plus 18:4n-3 (black currant group), for a period increasing with age. A control group was fed the essential fatty acids 18:2n-6 and 18:3n-3 only. For each group, delta 6, delta 5 and delta 9 desaturase activities were measured in liver microsomes, and fatty acid composition was determined in microsomal phospholipids. Desaturase activity varied as a function of age and dietary lipids. delta 6 Desaturation of 18:3n-3 was more sensitive to these factors while delta 6 desaturation of 18:2n-6 and delta 9 desaturation were more dependent on season than the other two. Desaturase activity was influenced more by the black currant than by the borage diet, especially at 6 and 9 months of age. A large proportion of arachidonic acid was maintained in the microsomes independent of the diet. Changes in the fatty acid composition did not strictly reflect the differences in desaturase activities. The effects of the two factors (age and diet) on the activities of the desaturases are complex, suggesting that the enzymes are susceptible to other factors as well.
Ulmann
L
L
Laboratoire de Physiologie Animale et de la Nutrition, Faculté des Sciences Mirandé, Dijon, France.
Blond
J P
JP
Maniongui
C
C
Poisson
J P
JP
Durand
G
G
Bézard
J
J
Pascal
G
G
D000375:Aging; D000818:Animals; D001835:Body Weight / Q000187:drug effects; D004041:Dietary Fats / Q000494:pharmacology*; D044943:Fatty Acid Desaturases / Q000378:metabolism*; D005227:Fatty Acids / Q000032:analysis*; D005228:Fatty Acids, Essential / Q000494:pharmacology*; D008099:Liver / Q000254:growth & development*; D008297:Male; D008862:Microsomes, Liver / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism*; D009929:Organ Size / Q000187:drug effects; D010743:Phospholipids / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D012621:Seasons
D004041:Dietary Fats; D005227:Fatty Acids; D005228:Fatty Acids, Essential; D010743:Phospholipids; D044943:Fatty Acid Desaturases