Neuroblastoma and Alzheimer's disease brain cells contain aromatase activity

Human brain steroidogenic mechanisms, particularly aromatase, have been investigated in healthy and diseased conditions. Aromatase activity was measured in differentiated and undifferentiated neuroblastoma cell lines from mouse (TMN) and human (5H SY5Y) and in human post mortem brain samples. Neuroblastomas show much higher aromatase activity than human brain samples. Homogenates of adult human male and female cortex and frontal and temporal areas of both Alzheimer's and control patients all show considerably lower activity. The temporal area has significantly higher aromatase activity than the frontal. Aromatisation activity in differentiated neuroblastoma cells of both species is lower than in undifferentiated cells. These results are consistent with an inverse relationship between brain estrogen formation and stage of neuronal differentiation and the hypothesis that aromatase may be involved in the early stages of neuronal growth. Significant but variable activities of other androgen-metabolising enzymes, such as 5 alpha-reductase, 3 alpha/beta-hydroxysteroid dehydrogenases, and 17 beta-hydroxysteroid dehydrogenase, which generate a spectrum of regulatory molecules, are also found.