Influence on the myocardial and blood activity course of the characteristics of the labelled fatty acid injected i.v. into mice.

In order to choose a labelled fatty acid (FA) for the external study of myocardial metabolism, FAs that are different in chain length, saturation, nature and position of the radioactive label, are injected i.v. into mice. Myocardial and blood activities are measured at various times p.i. It appears that hexadecanoic and hexadecenoic acids, iodine labelled in omega position, have the highest maximal myocardial activity among all the FAs studied. Furthermore, the myocardial and blood time-activity course is similar for both FAs. As unsaturated FAs have apparently a higher myocardial fixation in man than the saturated ones, 123I 16 iodo-9 hexadecenoic acid has been selected and seems well suited for the study of myocardial metabolism.