Radioiodinated fatty acids for myocardial imagine: effects on chain length.

Terminally iodinated long-chain fatty acids have been used experimentally and clinically as myocardial imaging agents. Six omega-iodo fatty acids (I(CH2)n CO2H, where n = 10, 12, 15, 18, 21, 26) have been synthesized and tested in rats. Myocardial extraction values and heart-to-blood ratios are affected by chain length. Extraction is shown to be highest for n = 18 and 21, as are heart-to-blood ratios at 5 min. The cellular fate of the fatty acid changes form that of beta -oxidation for n less than or equal to 15 to predominantly triglyceride storage for n = 18 and 21, as shown by analysis of rat heart homogenates by thin layer chromatography at two time intervals.