Astrocytes cultured in vitro produce estradiol-17β and express aromatase cytochrome P-450 (P-450 AROM) mRNA

Zwain, Ismail; Yen, S. S. C.; Cheng, C. Yan

doi:10.1016/s0304-4165(96)00115-8

Cited by 75 publications

(45 citation statements)

References 52 publications

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“…Similar observations dealing with the regulation of aromatase activity by androgens have been reported in the brain of the rat (Roselli & Resko 1984, Zwain et al 1997, Resko et al 2000. Below a threshold of 100 ng/ml testosterone the Leydig cell increase of estradiol output is the consequence of either post-transcriptional events and/or use of available mRNAs without transcriptional effects (which may indeed explain the slight diminution of the amount of P450arom mRNA; Fig.…”

Section: Discussionsupporting

confidence: 76%

Regulation of cytochrome P450 aromatase gene expression in adult rat Leydig cells: comparison with estradiol production

Genissel¹,

Levallet²,

Carreau³

2001

Journal of Endocrinology

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Regulation of aromatase gene expression in purified rat Leydig cells has not yet been investigated. Therefore, using a highly specific quantitative RT-PCR method, we have measured the amount of cytochrome P450 aromatase (P450arom) mRNA and aromatase activity in mature rat Leydig cells submitted to various treatments during 24 h. Estradiol production was enhanced in a dose-related manner in the presence of testosterone, the maximum (28% increase) being obtained with 200 ng/ml. Related to the P450arom mRNA levels, a decrease was observed in the presence of low concentrations (50 and 100 ng/ml) of testosterone, then a 20% increase of the amount of transcripts was recorded for the higher concentrations (200-500 ng/ml). The same result was obtained in the presence of 5 -dihydrotestosterone (an androgen resistant to aromatase activity). The addition of ovine LH (oLH; 0·1-50 ng/ml) to the Leydig cell culture medium induced a dose-related augmentation of estradiol output up to 10 ng/ml oLH, although a decrease was observed with 50 ng/ml when compared with maximal values. mRNA levels slightly decreased in the presence of low concentrations (0·1-1 ng/ml) of oLH, an effect that was abolished by the addition of testosterone; mRNA levels were increased by oLH (5-10 ng/ml) 35 and 75% respectively in the absence and presence of testosterone (when compared with Leydig cells incubated without treatment). With 50 ng/ml oLH, a large augmentation (twofold) of the P450arom mRNA level either without or with testosterone was observed. Dibutyryl cyclic AMP (1 mM) mimicked the effect of oLH. The half-life of the P450arom mRNAs was twofold increased in the presence of testosterone and oLH when compared with the half-life in the absence of treatment (5·8 0·6 h). Taken together, our data have demonstrated that, in freshly isolated Leydig cells from mature rat testes, the regulation of aromatase expression and enzymatic activity is under LH (through cyclic AMP) and steroid control; moreover seminiferous tubule-secreted factor(s) are also involved. Therefore, rat Leydig cell aromatase is controlled at both transcriptional and post-transcriptional steps by endocrine and/or locally produced modulators.

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Section: Discussionsupporting

confidence: 76%

Regulation of cytochrome P450 aromatase gene expression in adult rat Leydig cells: comparison with estradiol production

Genissel¹,

Levallet²,

Carreau³

2001

Journal of Endocrinology

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“…Steroids are known to be metabolized in the brain, e.g. differentiating neuroblastoma cells [23] and brain astrocytes [24] have been reported to produce 17β-oestradiol. Since it was found recently that 17β-HSD type 2 was not expressed in human temporal lobe [25], human SCHAD may play a highly significant role in steroid metabolism in brain.…”

Section: Discussionmentioning

confidence: 99%

Intrinsic alcohol dehydrogenase and hydroxysteroid dehydrogenase activities of human mitochondrial short-chain L-3-hydroxyacyl-CoA dehydrogenase

Yang

Schulz

et al. 1999

Biochemical Journal

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The alcohol dehydrogenase (ADH) activity of human shortchain -3-hydroxyacyl-CoA dehydrogenase (SCHAD) has been characterized kinetically. The k cat of the purified enzyme was estimated to be 2.2 min −" , with apparent K m values of 280 mM and 22µM for 2-propanol and NAD + , respectively. The k cat of the ADH activity was three orders of magnitude less than the -3-hydroxyacyl-CoA dehydrogenase activity but was comparable with that of the enzyme's hydroxysteroid dehydrogenase (HSD) activity for oxidizing 17β-oestradiol [He, Merz, Mehta, Schulz and Yang (1999)

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“…The expression of estrogen receptors (ERs) prevails in sensory neurons [24]. In contrast to brain neural cells [25, 26, 27, 28, 29]and to sensory neurons [30], the presence of aromatase activity (the enzyme that irreversibly converts testosterone into estradiol) in MN has still not been demonstrated, and it is agreed that circulating and not the in situ biosynthesized estrogen activates the ER cascade [31, 32]. …”

Section: Introductionmentioning

confidence: 99%

Receptors to Steroid Hormones and Aromatase Are Expressed by Cultured Motoneurons but Not by Glial Cells Derived from Rat Embryo Spinal Cord

et al. 2004

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The aim of this study was to examine the expression of aromatase and receptors to steroid hormones in cultured motoneurons (MNs). We first developed an original method for obtaining rat MN cultures. Dissociated E15 rat spinal cords were purified using metrizamide and bovine serum albumin density gradients, and cells were then seeded on the culture substratum. We optimized the culture parameters and found that simple addition of rat muscle extract (ME) and conditioned culture medium (CM) from glial cell lines (GCL) derived from spinal cord were sufficient to obtain almost pure MN cultures. MNs were characterized by the presence of specific MN markers and electrophysiology. MNs could be kept alive for 2 weeks. We demonstrate that ME and CM are essential for MN development and survival respectively. Immunocytochemistry and aromatase activity assay indicated the presence of androgen and estrogen receptors as well as aromatase in MNs but not in GCL. This is the first report demonstrating the presence of both female and male sex hormone receptors and a key enzyme in steroid hormone metabolism in MNs and its absence in GCL, at least in our culture conditions. This in vitro model appears to be valuable for elucidating the impact of the sex hormone circuit in neuronal maturation. The relevance of this model for the comprehension of neurodegenerative diseases is discussed.

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Astrocytes cultured in vitro produce estradiol-17β and express aromatase cytochrome P-450 (P-450 AROM) mRNA

Cited by 75 publications

References 52 publications

Regulation of cytochrome P450 aromatase gene expression in adult rat Leydig cells: comparison with estradiol production

Regulation of cytochrome P450 aromatase gene expression in adult rat Leydig cells: comparison with estradiol production

Intrinsic alcohol dehydrogenase and hydroxysteroid dehydrogenase activities of human mitochondrial short-chain L-3-hydroxyacyl-CoA dehydrogenase

Receptors to Steroid Hormones and Aromatase Are Expressed by Cultured Motoneurons but Not by Glial Cells Derived from Rat Embryo Spinal Cord

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