Myocradial extraction of 1-[{sup 11}C] betamethylheptadecanoic acid
- Harvard Medical School, Boston, MA (United States); and others
Betamethylheptadecanoic acid (BMHA) is a branched chain fatty acid analog that is transported into myocardial cells by the same long chain fatty acid carrier protein mechanism as natural fatty acids, but cannot be completely catabolzied and accumulates in the tissue. Thus, {sup 11}C-labeled BMHA is a useful tracer for the noninvasive evaluation of myocardial fatty acid utilization by positron emission tomography (PET). As a prelude to PET studies, the metabolism of BMHA was studied by classical techniques. The authors measured the net extraction fraction (E{sub n}) of 1-[{sup 11}C]-beta-R,S-methylheptadecanoic acid (1-[{sup 11}C]BMHA) and compared it to that of natural fatty acids in dogs, using arterial/venous measurements and a mathematical model. Two groups of conditioned dogs were studied. In the first group, measurements were made under fasting (normal control) conditions and in the second group, measurements were made during glucose and insulin infusion. Myocardial blood flow, and the extraction/utilization of other substrates (glucose, oxygen and lactate) were also measured. For natural fatty acids in the basal state, E{sub n}(FA) was 0.335. After glucose/insulin infusion, this value decreased to 0.195. The 1-[{sup 11}C]BMHA showed a similar decrease in E{sub n}(BMHA) from 0.220 in the control group to 0.100 in the group treated with glucose/insulin infusion. Preliminary PET studies with 1-[{sup 11}C]BMHA verified the validity of performing these measurements noninvasively. The results of these studies indicate that rates of fatty acid metabolism in the myocardium can be determined from steady-state concentrations of 1-[{sup 11}C]BMHA. 36 refs., 6 figs., 4 tabs.
- OSTI ID:
- 135832
- Journal Information:
- Journal of Nuclear Medicine Technology, Vol. 35, Issue 3; Other Information: PBD: Mar 1994
- Country of Publication:
- United States
- Language:
- English
Similar Records
Validity of estimates of myocardial oxidative metabolism with carbon-11 acetate and positron emission tomography despite altered patterns of substrate utilization
Radiolabeled acetate kinetics and tricarboxylic acid cycle flux in the rat heart