Aromatase Is Increased in Astrocytes in the Presence of Elevated Pressure

• Published in: Endocrinology (Philadelphia) 2011-01, Vol.152 (1), p.207-213
• Main Authors: Gatson, J. W, Simpkins, J. W, Yi, K. D, Idris, A. H, Minei, J. P, Wigginton, J. G
• Format: Article
• Language: English
• Subjects: Androstenedione; Androstenedione - metabolism; Animals; Aromatase; Aromatase - metabolism; Astrocytes; Astrocytes - cytology; Astrocytes - enzymology; Biological and medical sciences; Brain; Cell death; Cell Line; DNA Damage; Estrogens; Estrone; Estrone - metabolism; Fundamental and applied biological sciences. Psychology; Gene Expression Regulation, Enzymologic; Glia; Glioma; Glioma cells; Head injuries; Neuronal-glial interactions; Neurons; Polymerase chain reaction; Pressure; Proteins; Rats; RNA; RNA - genetics; RNA - metabolism; Traumatic brain injury; Vertebrates: endocrinology
• ISSN: 0013-7227; 1945-7170; 1945-7170
• DOI: 10.1210/en.2010-0724

After traumatic brain injury (TBI), a progressive injury and death of neurons and glia leads to decreased brain function. Endogenous and exogenous estrogens may protect these vulnerable cells. In this study, we hypothesized that increased pressure leads to an increase in aromatase expression and estrogen production in astrocytes. In this study, we subjected rat glioma (C6) cells and primary cortical astrocytes to increased pressure (25 mm Hg) for 1, 3, 6, 12, 24, 48, and 72 h. Total aromatase protein and RNA levels were measured using Western analysis and RT-PCR, respectively. In addition, we measured aromatase activity by assaying estrone levels after administration of its precursor, androstenedione. We found that increased pressure applied to the C6 cells and primary cortical astrocytes resulted in a significant increase in both aromatase RNA and protein. To extend these findings, we also analyzed aromatase activity in the primary astrocytes during increased pressure. We found that increased pressure resulted in a significant (P < 0.01) increase in the conversion of androstenedione to estrone. In conclusion, we propose that after TBI, astrocytes sense increased pressure, leading to an increase in aromatase production and activity in the brain. These results may suggest mechanisms of brain estrogen production after increases in pressure as seen in TBI patients. Individuals suffering from traumatic brain injury that experience positive outcomes may produce more aromatase and estrogens as a result of increased pressure; the increase in estrogens in the brain may result in a reduction in edema, oxidative stress, inflammation, cognitive deficits, and ultimately death.