Figure 13.
PET ROI analysis of images from living animals reflects hepatic FESP retention, D2R levels and D2R mRNA levels in Ad-CMV-D2R infected mice. Nude mice were injected through the tail vein with 5x106 to 9x109 pfu of Ad-CMV-D2R virus, to produce varying levels of D2R reporter gene expression. FESP was injected through the tail vein from 2 to 60 days after viral injection. Three hours after FESP injection, the mice were imaged in the ACAT PET scanner. The mice were then sacrificed, and their livers were removed and homogenized. Samples from each liver were analyzed for FESP and labeled FESP metabolites, [3H]spiperone binding activity, and D2R mRNA and GAPDH mRNA levels. FESP metabolites were 1.0 ± 0.6 %ID/g liver. (A) in vivo hepatic [18F] retention (measured by image analysis) as a function of in vitro hepatic FESP retention (measured by well counting). Note that the contribution of hepatic FESP metabolites has been removed from the values determined for FESP retention by well counting, but remain in the image data and contribute to a non-zero intercept. (B) in vivo analysis of hepatic [18F] retention as a function of hepatic D2R levels, measured by [3H]spiperone binding. (C) in vivo analysis of hepatic [18F] retention as a function of GAPDH-normalized levels of hepatic D2R mRNA, measured by Northern blot analysis.