The turnover rate of 14C-NE was studied regionally in males of 4 strains of inbred mice. It was found that the highest uptake and most rapid disappearance of this amine was exhibited, in declining order, by the hippocampus, hypothalamus, frontal cortex, and amygdala. Of the 4 strains studied, DBA/2J and SJL/J shared equally the highest turnover rates, while C3H/HeJ consistently exhibited the slowest turnover rates in all the brain regions examined. Because there were no accompanying analyses for bound and free NE, the conclusions regarding the significance of some of the differences found in this study are somewhat limited.