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Testosterone metabolism in brain cells and membranes
F Celotti1, R C Melcangi, P Negri-Cesi
1Institute of Endocrinology, University of Milan, Italy.
The Journal of Steroid Biochemistry and Molecular Biology
|January 1, 1991
Summary
Hormonal steroids impact the central nervous system (CNS). Testosterone (T) is converted to active metabolites like 5 alpha-dihydrotestosterone (DHT) and estrogens, influencing brain activity.
Area of Science:
- Neuroendocrinology
- Steroid biochemistry
Background:
- Hormonal steroids target the central nervous system (CNS), acting through genomic and membrane mechanisms.
- Steroid efficacy often depends on conversion to active metabolites, such as testosterone (T) to 5 alpha-dihydrotestosterone (DHT) and estrogens.
Purpose of the Study:
- To clarify the distribution and relative roles of 5 alpha-reductase and aromatase enzymes within CNS structures.
- To investigate the cellular localization and activity of these enzymes in different brain cell types.
Main Methods:
- Isolation of neurons, astrocytes, and oligodendrocytes from male rat brains using density gradient ultracentrifugation.
- Culturing of neurons and glial cells to assess enzyme activity.
- Enzymatic assays for 5 alpha-reductase and aromatase activity.
Main Results:
- 5 alpha-reductase is highly concentrated in white matter, associated with myelin membranes, suggesting a role in membrane-mediated CNS events.
- Neurons exhibit higher 5 alpha-reductase activity than oligodendrocytes and astrocytes in converting T to DHT.
- Only neurons possess aromatase activity, indicating glial cells cannot convert T to estrogens.
Conclusions:
- The differential distribution and activity of 5 alpha-reductase and aromatase in CNS cells suggest specific roles for steroid metabolites in neuronal and glial functions.
- Neuronal conversion of T to DHT and estrogens highlights the importance of these metabolites in brain function.