Influence of fatty acid backdiffusion on compartmental analysis of external detection curves obtained with 123-iodohexadecenoic acid in isolated rat heart.

In isolated rat hearts, we investigated a possible backdiffusion of fatty acids and tried to determine whether it impaired our compartmental analysis of myocardial time-radioactivity curves obtained with an iodinated fatty acid, 16-iodo-9-hexadecenoic acid (IHA). Backdiffusion was not observed directly in the coronary effluents but was estimated by analysis of the external detection curves. Furthermore, when backdiffusion was not taken into account in the mathematical analysis, we obtained similar data on IHA intramyocardial metabolism.