Modulation of lipid chylomicron-synthesizing enzymes in rats by the dietary (n-6):(n-3) fatty acid ratio.
The effect of diets with various (n-6):(n-3) polyunsaturated fatty acid (PUFA) ratios and a constant polyunsaturated: saturated fatty acid ratio on the basal activity of chylomicron lipid synthesizing enzymes was investigated in rat intestinal microsomes. Enzymes studied were: acyl-CoA:cholesterol acyltransferase (ACAT); acyl-CoA:lysophosphatidylcholine acyltransferase (MGAT) and acyl-CoA:1,2-diacylglycerol acyltransferase (DGAT). Results showed that after a 4-wk feeding period, ACAT, ACLAT and DGAT basal activities were significantly enhanced by the dietary fatty acids of the (n-3) series, whereas MGAT activity was not affected. When the highest (n-6):(n-3) ratio (51.0) was compared with the lowest (0.8), the increase attained was about 58, 76 and 73% for ACAT, ACLAT and DGAT, respectively. Fatty acid composition of microsomal lipids was drastically altered by the diets because (n-3) PUFA replaced the (n-6) series as the dietary (n-6):(n-3) ratio was lowered. These compositional changes could explain the observed modification in the membrane-bound enzyme activities. We suggest that (n-3) PUFA ingestion leads to an enhanced velocity of chylomicron synthesis in rats.
Chautan
M
M
Unité 130, Institut National de la Santé de la Recherche Médicale, Marseille, France.
Charbonnier
M
M
Léonardi
J
J
André
M
M
Lafont
H
H
Nalbone
G
G
D000217:Acyltransferases / Q000378:metabolism*; D000284:Administration, Oral; D000818:Animals; D002914:Chylomicrons / Q000096:biosynthesis*; D004041:Dietary Fats / Q000008:administration & dosage / Q000378:metabolism / Q000494:pharmacology*; D005231:Fatty Acids, Unsaturated / Q000008:administration & dosage / Q000378:metabolism / Q000494:pharmacology*; D005395:Fish Oils / Q000008:administration & dosage / Q000378:metabolism / Q000494:pharmacology; D007413:Intestinal Mucosa / Q000378:metabolism; D007422:Intestines / Q000187:drug effects* / Q000201:enzymology; D008297:Male; D008861:Microsomes / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains
D002914:Chylomicrons; D004041:Dietary Fats; D005231:Fatty Acids, Unsaturated; D005395:Fish Oils; D000217:Acyltransferases