Long-chain F-18 fatty acids for the study of regional metabolism in heart and liver; odd-even effects of metabolism in mice.
In view of the potential usefulness of fluorine-tagged fatty acids in the study of regional metabolism in the heart and liver, the time courses of uptake and release of 9,10-[18F]fluorostearic acid, 2-[18F]fluorostearic acid, 16-[18F]fluorohexadecanoic acid, 17-[18F]fluoroheptadecanoic acid have been investigated in several organs of NMRI mice. Whereas 2-[18F]fluorostearic acid shows very little uptake in the heart muscle but an increasing accumulation in the liver, the fatty acids with the F-18 label in the middle or at the end of the carbon chain exhibit uptake and elimination behavior similar to that of the analogous C-11-labeled compounds. After rapid concentration in the heart within 1 min, clearance takes place with fast and slow components. 16-[18F]fluorohexadecanoic acid and 17-[18F]fluoroheptadecanoic acid have different half-times of elimination. These differences are also reflected by the fact that nearly all the activity present in the heart can be recovered as fluoride(F-18) in the case of 17-[18F]fluoroheptadecanoic acid, whereas practically no fluoride was found among the metabolites of 16-[18F]fluorohexadecanoic acid. Similar differences were observed for the F-18 activity in bone. The results can be interpreted in terms of the odd-even rule: beta oxidation of even-numbered fatty acids ends up with [18F]fluoroacetic acid, whereas the odd-numbered fatty acids give rise to beta-[18F]fluoropropionic acid. Only in the latter case does dehalogenation take place leading to free fluoride, whereas fluoroacetic acid undergoes further reactions in the citric acid cycle.
D000818:Animals; D001842:Bone and Bones / Q000378:metabolism; D003652:Decanoic Acids / Q000378:metabolism; D005227:Fatty Acids / Q000378:metabolism*; D005260:Female; D005461:Fluorine; D006321:Heart / Q000000981:diagnostic imaging*; D008099:Liver / Q000000981:diagnostic imaging* / Q000378:metabolism; D051379:Mice; D009206:Myocardium / Q000378:metabolism; D010084:Oxidation-Reduction; D011868:Radioisotopes; D013229:Stearic Acids / Q000378:metabolism; D013997:Time Factors; D014055:Tomography, Emission-Computed / Q000379:methods
D003652:Decanoic Acids; D005227:Fatty Acids; D011868:Radioisotopes; D013229:Stearic Acids; D005461:Fluorine