FIGURE 4.

PDE10 expression is confined to testis and striatum. Mouse organs (A) and brain regions (B) were homogenized and analyzed in Western blots using a newly generated antiserum raised against the GAF domains of PDE10. Recombinant human PDE10A1 was applied as a positive control. Shown is one representative blot of three. Larger sections of Western blots are shown in supplemental Fig. 3. C, primary murine Leydig cells (10⁶) were stimulated by the indicated concentrations of luteinizing hormone in the absence or presence of the PDE10 inhibitor TP-10, and testosterone release (3 h at 34 °C) was measured by radioimmunoassay. (*, p < 0.05; **, p < 0.01.) D, stimulation of cAMP-degrading activity in homogenates of murine striatum by increasing concentrations of the GAF domain ligand 7-CH-cAMP was assessed at a substrate concentration of 0.03 μm cAMP. Values are means ± standard error of the mean.