Dual tracer autoradiographic study of beta-methyl-(1-14C) heptadecanoic acid and 15-p-(131I)-iodophenyl-beta-methylpentadecanoic acid in normotensive and hypertensive rats.

The myocardial distribution of 15-p-(/sup 131/I)iodophenyl-3-(R,S)-methylpentadecanoic acid (BMPDA) and 1(/sup 14/C)-3-(R,S)-methylheptadecanoic acid (BMHDA) was compared in normotensive and hypertensive rats using quantitative dual tracer autoradiographic techniques. The myocardial distribution of carbon-14 (/sup 14/C) BMHDA and iodine-131 (/sup 131/I) BMPDA was nearly homogeneous in the normotensive rats, while both tracers showed similar, though very heterogeneous, distribution in hypertensive hearts with decreased uptake in the endocardial region. Our data demonstrate that myocardial distribution of (/sup 131/I)BMPDA was essentially the same as (/sup 14/C)BMHDA, and thus single photon emission computed tomographic imaging with /sup 123/I-labeled BMPDA could be useful for the detection of regional changes of myocardial fatty acid uptake in patients with prolonged and severe hypertension.