Phenylethanolamine N-methyl transferase expression in mouse thymus and spleen.

Catecholamines usually are found in neurons and chromaffin cells of mammals. In this study, surprisingly high levels of the epinephrine synthesizing enzyme phenylethanolamine N-methyl transferase (PNMT) were detected in the thymus of young mice. Levels of PNMT activity in the thymus were comparable to levels in the brainstem and were suppressed by the PNMT inhibitor LY134046.