Nuclear medicine program: Progress report for quarter ending March 31, 1988

In this report the results of several studies with radioiodinated fatty acid are described. Studies with the isolated Langendorff- perfused rat heart system have continued to evaluate the distribution of (I-125)-15-(p-iodophenyl)-3-R,S-methylpentadecanoic acid (BMIPP) in myocardial lipids after 15 min of perfusion. At this time period 38--44% of the endogenous radioactivity is associated with material chromatographing in the region of triglycerides, 18--21% in the region of diglycerides and only 6--10% in the area of free fatty acids. Thus, the isolated heart mimics the in vivo studies in demonstrating that the retention of radioiodinated BMIPP is associated with lipid storage products. In addition, the synthesis of the isomeric mixture of 9- and 10-(I-125)-labeled iodooleic acid via formation of the corresponding a boronic acid intermediate is also described. The isomeric radioiodinated product mixture shows good heart uptake and retention (5 min, 3.45% dose/gm; 30 min, 2.44% dose/gm; 60 min, 2.28% dose/gm) and demonstrate that this structural perturbation does not interfere with myocardial specificity.