Postprandial responses of individual fatty acids in subjects homozygous for the threonine- or alanine-encoding allele in codon 54 of the intestinal fatty acid binding protein 2 gene.
BACKGROUND
The affinity of intestinal fatty acid binding protein (FABP) for fatty acids is regulated by the polymorphism at codon 54 of the FABP2 gene (alanine-to-threonine shift). We found earlier that the threonine-encoding allele (Thr54) is associated with an increased postprandial lipemic response.


OBJECTIVE
We studied the postprandial responses of individual fatty acids in subjects homozygous for the Thr54 or alanine-encoding allele (Ala54).


METHODS
Oral-fat-loading tests were performed in 8 subjects homozygous for Thr54 and in 7 subjects homozygous for Ala54.


RESULTS
The postprandial responses of most of the 14-18-carbon fatty acids in chylomicron and VLDL triacylglycerols were significantly elevated in the Thr54 homozygotes whereas the relative increases in these fatty acids were not significantly different in both groups. The amounts of 20- and 22-carbon polyunsaturated fatty acids started to increase later than the amounts of shorter ones after the test meal, and the differences between the groups were mostly insignificant. The responses of chylomicron fatty acids correlated positively with postprandial insulin response in the Thr54 homozygotes and inversely in the Ala54 homozygotes. VLDL fatty acid responses correlated with fasting triacylglycerol concentrations in the Ala54 homozygotes but not in the Thr54 homozygotes.


CONCLUSIONS
The threonine-encoding allele of the FABP2 gene is associated with an increased postprandial response of 14-18-carbon fatty acids but not with changes in the relative amounts of individual fatty acids introduced to chylomicron triacylglycerols.
Agren
J J
JJ
Departments of Physiology, Clinical Nutrition, and Medicine, University of Kuopio, Kuopio, Finland. jyrki.agren@uku.fi
Vidgren
H M
HM
Valve
R S
RS
Laakso
M
M
Uusitupa
M I
MI
D000368:Aged; D000409:Alanine / Q000235:genetics*; D000483:Alleles; D002352:Carrier Proteins / Q000235:genetics*; D015243:Cholesterol, VLDL / Q000032:analysis; D002914:Chylomicrons / Q000032:analysis; D003062:Codon / Q000737:chemistry; D000071438:Fatty Acid-Binding Protein 7; D050556:Fatty Acid-Binding Proteins; D005227:Fatty Acids / Q000097:blood*; D005260:Female; D006720:Homozygote; D006801:Humans; D007328:Insulin / Q000097:blood; D007422:Intestines / Q000502:physiology; D008055:Lipids / Q000097:blood; D008297:Male; D008875:Middle Aged; D009363:Neoplasm Proteins; D011110:Polymorphism, Genetic; D019518:Postprandial Period; D013912:Threonine / Q000235:genetics*; D013997:Time Factors; D025521:Tumor Suppressor Proteins
D002352:Carrier Proteins; D015243:Cholesterol, VLDL; D002914:Chylomicrons; D003062:Codon; C493404:FABP2 protein, human; C107608:FABP7 protein, human; C493405:Fabp2 protein, mouse; D000071438:Fatty Acid-Binding Protein 7; D050556:Fatty Acid-Binding Proteins; D005227:Fatty Acids; D007328:Insulin; D008055:Lipids; D009363:Neoplasm Proteins; D025521:Tumor Suppressor Proteins; D013912:Threonine; D000409:Alanine