Multiple forms of aryl acylamidase in regional tissues of developing rat brain

The specific activities of two forms of aryl acylamidase (AAA) were examined in 7 regions of the developing rat brain, plus the remainder of the brain and the whole brain. AAA-1 activity peaked at 15 days old in all brain regions studied except the whole brain where it peaked at 22 days of age. AAA-2 activity peaked between 15 and 29 days old in most brain regions studied except corpus striatum and hippocampus where the AAA-2 activity peaked before 15 days old. In all areas and at all time periods, with the exception of CS after 15 days of age, AAA-2 activity was much higher than that of AAA-1. The developmental pattern of AAA-1 is generally the same in the different brain regions while that of AAA-2 shows more regional specificity. These results indicate that neither AAA-1 nor AAA-2 may be associated with amine N-acetyltransferase in the brain which has an entirely different developmental pattern.