Metabolism of methyl-branched iodo palmitic acids in cultured hepatocytes.
The metabolic fate of methyl-branched iodo fatty acids was studied in primary culture of rat hepatocytes. We compared 16-iodo-2-R,S-methyl palmitic acid (2-Me), which can be beta oxidized, with 16-iodo-3-R,S-methyl palmitic acid (3-Me) which can be beta oxidized only after an initial alpha oxydation and with 16-iodo-2,2-dimethyl palmitic acid (2,2-Me2) and 16-iodo-3,3-dimethyl palmitic acid (3,3-Me2) which cannot be beta oxidized at all. The normal fate of natural fatty acids was given by comparative experiments with [1-14C] palmitic acid. Monomethyl-branched iodo fatty acids were taken up in the same range as palmitic acid but more than dimethyl-branched iodo fatty acids. After a 15-h incubation, acido-soluble products (ASP) accounted for 75% of the radioactivity taken up as 16-iodo-2-methyl palmitic acid, 50% as other methyl-branched iodo fatty acids and only 30% as palmitic acid, which indicated that all the methyl-branched iodo fatty acids underwent a strong deiodination process. Fatty acids were esterified in the following order: palmitic acid greater than 16-iodo-3-R,S-methyl palmitic acid greater than 16-iodo-2-R,S-methyl palmitic acid greater than 16-iodo-2,2-dimethyl palmitic acid greater than 16-iodo-3,3-dimethyl palmitic acid. Cultured hepatocytes, labelled for 3 h with the various fatty acids and reincubated for 12 h without fatty acid, secreted large amounts of free dimethyl-branched iodo fatty acids as compared to the monomethyl ones and palmitic acid.(ABSTRACT TRUNCATED AT 250 WORDS)
Thomas
G
G
CHU Saint Antoine, URA CNRS, Paris, France.
Pépin
D
D
Loriette
C
C
Vidal
M
M
Apparu
M
M
Coornaert
S
S
Chambaz
J
J
Béréziat
G
G
D000818:Animals; D002478:Cells, Cultured; D066298:In Vitro Techniques; D007457:Iodine Radioisotopes; D008099:Liver / Q000378:metabolism*; D008297:Male; D010169:Palmitic Acids / Q000493:pharmacokinetics*; D051381:Rats
D007457:Iodine Radioisotopes; D010169:Palmitic Acids