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.