Synthesis and preliminary evaluation of [1-11C]hexanoate as a PET tracer of fatty acid metabolism

The potential of [1-11C]hexanoate (11C-HA) as a radiopharmaceutical assessing fatty acid metabolism of the myocardium and brain tissues by PET studies was evaluated.11C-HA was synthesized by the Grignard reaction of pentylmagnesium bromide and11CO2.11C-HA, [1-14C]acetate and [3H]deoxyglucose were simultaneously injected i.v. into mice, and the tissue distribution of the three radionuclides was measured. In the heart, high uptake and rapid clearance of11C and14C was found. The brain uptake of11C was twice as high as that of14C, and both11C and14C decreased slowly compared to the heart. The level of3H increased with time in both the heart and brain. In fasting conditions, the uptake of11C by the heart was enhanced and the level of3H decreased with time. The brain uptake of11C and3H was also enhanced. The fasting conditions did not affect the distribution of14C. The radiation absorbed dose of11C-HA was also estimated.