Immunohistochemical evidence of the presence of aromatase P450 in the rat hypophysis

Carretero, José; Vázquez, Gabriel; Blanco, E; Rubio, Manuel Pablo; Santos, Marinilce Fagundes dos; Martín-Clavijo, Agustín; Torres, Jose; Vázquez, Ricardo

doi:10.1007/s004410051248

Cited by 31 publications

(29 citation statements)

References 34 publications

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“…In the present study 3 -HSD was localized in individual cells randomly scattered throughout the anterior pituitary in both ovariectomized and pro-oestrous female rats. These results are in complete agreement with those of previous studies showing a scattered cellular distribution of aromatase P450 in female rat pituitaries and 17 -HSD in non-tumorous and adenomatous human pituitaries (Carretero et al 1999, Green et al 1999. Our data provide evidence that changes in pituitary steroidogenic activity can be correlated with ovarian endocrine function.…”

Section: Discussionsupporting

confidence: 93%

“…A significant increase was observed in the percentage of 3 -HSD-immunopositive cells in the pituitary of ovariectomized animals compared with pro-oestrous rats. Carretero et al (1999) reported similar results in the expression of aromatase P450 in the rat pituitary. These authors demonstrated a stronger aromatase reaction in dioestrus than in pro-oestrus or oestrus.…”

Section: Discussionsupporting

confidence: 63%

“…Little is known about the role played by steroidogenic enzymes in the regulation of pituitary cell function, including hormone synthesis and/or release. Recently, Carretero et al (1999) demonstrated that the enzyme aromatase P450, which is involved in androgen metabolism, is expressed in the adult rat pituitary, suggesting that this enzyme may play a role in the regulation of adenohypophyseal cell morphology. Green et al (1999) reported that 17 -hydroxysteroid dehydrogenase (17 -HSD) isoforms, which reversibly catalyse the final step in the formation of oestradiol from oestrone and that of testosterone from androstenedione, are present in human pituitary adenomas; this is consistent with the view that this enzyme may be involved in the regulation of oestradiol synthesis at local cellular level.…”

Section: Discussionmentioning

confidence: 99%

“…These authors demonstrated a stronger aromatase reaction in dioestrus than in pro-oestrus or oestrus. Stronger expression was also noted in the pituitaries of male rats compared with those of females (Carretero et al 1999). In human pituitary tumours, Green et al (1999) showed that, in contrast to surgically removed pituitary tissue, most of the adenomatous cells in vitro were strongly immunopositive for 17 -HSD, suggesting that culture conditions can stimulate the expression of the enzyme gene.…”

Section: Discussionmentioning

confidence: 99%

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Expression of 3 beta-hydroxysteroid dehydrogenase/isomerase in the female rat pituitary

Vidal

Román²,

Moya³

et al. 2000

Journal of Endocrinology

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-Hydroxysteroid dehydrogenase/isomerase (-HSD)catalyses an essential step in the biosynthesis of steroid hormones and is widely distributed in peripheral steroid target organs. The present report describes for first time the expression of this enzyme in the pituitary of female rats. Immunohistochemistry at the light microscopic level was performed on pro-oestrous and ovariectomized rat pituitaries. Immunoreactive cells were scattered and randomly distributed throughout the anterior lobe, whereas cells located in the posterior lobe and pars intermedia were immunonegative. Differences were observed in cell morphology and in the number of 3 -HSD-immunopositive cells between ovariectomized and pro-oestrous female rat pituitaries, suggesting that steroidogenic activity is affected by ovarian endocrine function. Apart from adenohypophyseal immunoreactive cells, 3 -HSD immunopositivity was also noted in endothelial cells of almost all pituitary capillaries located in the anterior and posterior lobes.

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Section: Discussionsupporting

confidence: 93%

Section: Discussionsupporting

confidence: 63%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

See 2 more Smart Citations

Expression of 3 beta-hydroxysteroid dehydrogenase/isomerase in the female rat pituitary

Vidal

Román²,

Moya³

et al. 2000

Journal of Endocrinology

View full text Add to dashboard Cite

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“…It has also been suggested that the expression of brain aromatase influences the brain-pituitary-gonadal axis of reproductive physiology, especially with respect to steroid feedback onto gonadotropin and/or gonadotropin-releasing hormone (GnRH) secretion (MacLusky & Naftolin 1981, Khan et al 1999; however, little attention has been received to address this hypothesis. In addition to the brain, the teleost pituitary highly expresses the CYP19A2 gene (Gelinas et al 1998, Menuet et al 2003, Goto-Kazeto et al 2004, whereas the mammalian pituitary is generally considered aromatase-negative although the rat pituitary is known to express this enzyme (Callard et al 1983, Carretero et al 1999. This suggests that CYP19A2 gene may be important for the function of the pituitary gland in teleosts.…”

Section: Introductionmentioning

confidence: 98%

Molecular biology of channel catfish brain cytochrome P450 aromatase (CYP19A2): cloning, preovulatory induction of gene expression, hormonal gene regulation and analysis of promoter region

Kazeto¹,

Trant²

2005

Journal of Molecular Endocrinology

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Cytochrome P450 aromatase (CYP19) converts androgens to estrogens. Unlike mammals, teleosts have two CYP19 genes, expressed differentially in ovary (CYP19A1) and neuronal tissues (CYP19A2). The primary purpose of this study was to demonstrate the potential involvement of CYP19A2 in the reproductive endocrinology of teleosts. Channel catfish CYP19A2 (ccCYP19A2) cDNAs were isolated from the brain using a PCR-based strategy. The ccCYP19A2 cDNA putatively encodes 500 amino acids which conferred aromatase activity in transfected COS-7 cells. Additionally, an alternatively spliced transcript was isolated which lacks the first 122 amino acids and is catalytically inactive. The brain and the pituitary were predominant sources of ccCYP19A2 transcript and the abundance in both tissues acutely increased prior to spawning. This preovulatory induction of ccCYP19A2 gene in the pituitary is remarkably similar to the pattern of gene expression for luteinizing hormone-(LH ). Estradiol-17 (E 2 ) and testosterone enhanced the transcript abundance of ccCYP19A2 and LH in catfish pituitary cells cultured in vitro but the stimulatory effects of testosterone were abolished by an aromatase inhibitor, indicating an important role of E 2 , the product of CYP19A2 activity, in the regulation of CYP19A2 and LH . Structural and functional analysis of the 58-flanking region of the gene suggested that the sequence from -1076 to -435 bp is critical for the basal promoter activity in the pituitary. This report demonstrates that CYP19A2 functions as an important factor in the reproductive endocrinology of teleosts through the brain-pituitary-gonadal axis.

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In vitro immunoblockade of VIP inhibits the proliferation of pituitary prolactin cells

et al. 2005

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VIP is a peptide synthesised in the pituitary gland and is involved in the stimulation of prolactin secretion. However, to date it has not been determined whether VIP is able to regulate the proliferation of pituitary prolactin-producing cells, like other factors involved in the regulation of prolactin such as estradiol or dopamine. The aim of the present study was to address whether VIP is involved in regulating the proliferation of pituitary prolactin-secreting cells. Thus, we performed an in vitro study on monolayer cultures of rat pituitary cells, neutralising the possible paracrine effect of VIP by immunoblockade of the peptide and later determining the degree of proliferation of prolactin-secreting cells. The effects of immunoblockade were validated by determining the levels of VIP in the culture media, which were decreased (P < 0.01), and modifications in the patterns of the immunohistochemical reaction to prolactin-positive cells. Immunoblockade of VIP decreased the proliferation of pituitary prolactin-positive cells at all antibody concentrations analysed, mainly between 3 and 12 h (P < 0.01). Moreover, immunoblockade decreased the sizes of the cellular and nuclear areas, except at 1 h, at which point it only decreased the nuclear area of prolactin-positive cells. The results obtained suggest that-in the same way as it regulates the secretion of the hormone-VIP could be involved in regulating the proliferation of prolactin cells, like estradiol or dopamine.

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Immunohistochemical evidence of the presence of aromatase P450 in the rat hypophysis

Cited by 31 publications

References 34 publications

Expression of 3 beta-hydroxysteroid dehydrogenase/isomerase in the female rat pituitary

Expression of 3 beta-hydroxysteroid dehydrogenase/isomerase in the female rat pituitary

Molecular biology of channel catfish brain cytochrome P450 aromatase (CYP19A2): cloning, preovulatory induction of gene expression, hormonal gene regulation and analysis of promoter region

In vitro immunoblockade of VIP inhibits the proliferation of pituitary prolactin cells

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