Astrocytes cultured in vitro produce estradiol-17beta and express aromatase cytochrome P-450 (P-450 AROM) mRNA.
Aromatase cytochrome P-450 (P-450AROM) is an enzyme that catalyzes the conversion of androgen to estrogen. Estrogen plays an important role in the neuronal function by promoting the formation of dendrites and may be involved in protecting the neurons in the cerebral cortex against specific pathological conditions such as Alzheimer's disease. However, the cellular origin of estrogen in the brain is not known. The present study demonstrated for the first time the production of estradiol-17beta and expression of P-450AROM mRNA in astrocytes isolated from the cerebral cortex of neonatal rats. Immunocytochemical studies using a monospecific antibody against rat P-450AROM has shown that this enzyme was localized in the cytoplasm of astrocytes. Interleukin-1 (IL-1) has been shown to stimulate the proliferation and differentiation of astrocytes and to affect the aromatase activity in non-neuronal cells such as Sertoli, Leydig, and placental cells. Treatment of astrocytes with IL-1beta induced a dose-dependent inhibition of estradiol production. This inhibitory action of IL-1beta can be reversed by the addition of anti-IL-1beta antibody. Since astrocytes are involved in the synaptic reorganization in the brain by removing cellular debris and by providing the necessary biological factors for neuronal growth, the ability of astrocytes to produce estradiol-17beta and express P-450AROM mRNA in vitro suggests a new role for these cells in protecting and supporting neurons.
Zwain
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IH
The Population Council, Center for Biomedical Research, New York, NY 10021, USA.
Yen
S S
SS
Cheng
C Y
CY
D000818:Animals; D001141:Aromatase / Q000096:biosynthesis* / Q000235:genetics; D001253:Astrocytes / Q000378:metabolism*; D002478:Cells, Cultured; D002540:Cerebral Cortex / Q000378:metabolism; D004958:Estradiol / Q000096:biosynthesis*; D005260:Female; D006107:Granulosa Cells / Q000378:metabolism; D007375:Interleukin-1 / Q000494:pharmacology; D008297:Male; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000096:biosynthesis*; D051381:Rats
D007375:Interleukin-1; D012333:RNA, Messenger; D004958:Estradiol; D001141:Aromatase