scholarly journals Hormonal regulation of cytochrome P450 aromatase mRNA stability in non-luteinizing bovine granulosa cells in vitro

2006 ◽  
Vol 190 (1) ◽  
pp. 107-115 ◽  
Author(s):  
Malha Sahmi ◽  
Edmir S Nicola ◽  
Christopher A Price
Keyword(s):  
Cytochrome P450 ◽  
Granulosa Cells ◽  
Half Life ◽  
Hormonal Regulation ◽  
Hormonal Control ◽  
Transcriptional Level ◽  
P450 Aromatase ◽  
Cytochrome P450 Aromatase ◽  
Mrna Half Life

In the present study, we determined the potential for post-transcriptional regulation of cytochrome P450 aromatase (Cyp19), cytochrome P450 side-chain cleavage (Cyp11a) and 17β-hydroxysteroid dehydrogenase I (Hsd17b1) mRNA. Bovine granulosa cells were cultured in non-luteinizing conditions that permit long-term oestradiol secretion. Half-lives of mRNA were measured by Northern and/or reverse transcriptase (RT)-PCR after inhibition of gene transcription. In FSH-stimulated cells, the Cyp11a and Hsd17b1 mRNAs had half-lives greater than 12 h. The half-life of Cyp19 mRNA was significantly shorter at 3 h. The addition of the translation inhibitor cycloheximide to FSH-stimulated cells significantly increased Cyp19 mRNA half-life to approximately 12 h. Stimulation of cells with insulin resulted in Cyp19 mRNA half-life that was double (P<0.05) that in FSH-stimulated cells. We conclude that bovine Cyp19 mRNA is very labile under physiological conditions, and that Cyp19 expression is under hormonal control at a post-transcriptional level.

scholarly journals Insulin and IGF-I are necessary for FSH-induced cytochrome P450 aromatase but not cytochrome P450 side-chain cleavage gene expression in oestrogenic bovine granulosa cells in vitro

2002 ◽  
Vol 174 (3) ◽  
pp. 499-507 ◽  
Author(s):  
JM Silva ◽  
CA Price
Keyword(s):  
Gene Expression ◽  
Cytochrome P450 ◽  
Granulosa Cells ◽  
Side Chain ◽  
Mrna Levels ◽  
Side Chain Cleavage ◽  
P450 Aromatase ◽  
Chain Cleavage ◽  
Igf I

The earliest biochemical indicators of ovarian follicle deviation in cattle include lower oestradiol and free IGF concentrations in subordinate compared with dominant follicles. We determined if decreases in FSH, IGF-I or insulin cause decreased P450 aromatase (P450arom) or P450 cholesterol side-chain cleavage (P450scc) mRNA expression in oestrogenic bovine granulosa cells in vitro. In the first experiment, cells obtained from small follicles (2-5 mm diameter) were cultured in serum-free medium supplemented with physiological concentrations of FSH, IGF-I and insulin for 4 days. A decrease in specific hormone concentration was produced by replacing 70% of spent medium with medium devoid of FSH, insulin, or insulin and IGF-I on day 4 and again on day 5 of culture. Cultures were terminated on day 7. A reduction in FSH concentrations during the last 3 days of culture decreased P450arom and P450scc mRNA levels. A reduction in insulin reduced P450arom but not P450scc mRNA levels, and a reduction of both insulin and IGF-I concentrations further decreased P450arom mRNA levels and decreased P450scc mRNA levels. In a second experiment, cells obtained from small follicles (2-5 mm diameter) were cultured with insulin (100 ng/ml) without FSH for 4 days, and then insulin was withdrawn from the culture and FSH added for a further 3 days. The withdrawal of insulin decreased (P<0.02) oestradiol accumulation and reduced P450arom mRNA to below detectable levels, but did not affect P450scc mRNA levels. The addition of FSH transiently increased oestradiol secretion and P450arom mRNA levels, but P450arom mRNA levels were undetectable at the end of the culture period. The addition of FSH significantly enhanced P450scc mRNA levels and progesterone accumulation. These data demonstrated that a reduction of insulin-like activity reduced aromatase gene expression in bovine follicles without necessarily affecting progesterone synthetic capability, and thus may initiate follicle regression in cattle at the time of follicle divergence.

Cytochrome P450 Aromatase Promoter Usage in Bovine Granulosa Cells.

2012 ◽  
Vol 87 (Suppl_1) ◽  
pp. 578-578
Author(s):  
Fatiha Sahmi ◽  
Edmir Nicola ◽  
Gustavo Zamberlam ◽  
Christopher A. Price
Keyword(s):  
Cytochrome P450 ◽  
Granulosa Cells ◽  
P450 Aromatase ◽  
Cytochrome P450 Aromatase ◽  
Promoter Usage

A Dictyostelium prespore-specific gene is transcriptionally repressed by DIF in vitro

Development ◽  
1988 ◽  
Vol 103 (3) ◽  
pp. 519-524 ◽  
Author(s):  
A.E. Early ◽  
J.G. Williams
Keyword(s):  
Half Life ◽  
Stalk Cell ◽  
Specific Gene ◽  
Transcriptional Level ◽  
Mrna Half Life ◽  
Spore Cell ◽  
Transcriptional Controls

One important role of DIF, the stalk cell-specific inducer of Dictyostelium, may be to divert cells from the spore cell pathway of differentiation. The D19 gene encodes an mRNA which is highly enriched in prespore over prestalk cells in the migratory slug. We show, using a mutant defective in DIF accumulation, that the concentration of D19, and several other prespore mRNA sequences, decreases in the presence of exogenous DIF. There is evidence that both transcriptional and post-transcriptional controls operate to regulate expression of these genes. We have performed in vitro nuclear transcription and mRNA half-life analyses, and find that DIF acts at the transcriptional level to repress the accumulation of the D19 mRNA.

scholarly journals Immunohistochemical localization of cytochrome P450 aromatase in equine gonads.

1995 ◽  
Vol 43 (6) ◽  
pp. 571-577 ◽  
Author(s):  
J Almadhidi ◽  
G E Seralini ◽  
J Fresnel ◽  
P Silberzahn ◽  
J L Gaillard
Keyword(s):  
Cytochrome P450 ◽  
Granulosa Cells ◽  
Immunoblot Analysis ◽  
Immunofluorescent Staining ◽  
Interstitial Tissue ◽  
Experimental Conditions ◽  
Specific Staining ◽  
P450 Aromatase ◽  
Estrogen Synthesis ◽  
Cytochrome P450 Aromatase

Estrogens are the major steroids produced by equine gonads. To identify the cells responsible for estrogen synthesis, an antiserum against purified equine testicular cytochrome P450 aromatase was produced in rabbits. The reactivity and specificity of the antiserum were assessed by ELISA, immunoblot analysis, and immunoneutralization studies. Immunofluorescence microscopy demonstrated that in the male gonad, cytochrome P450 aromatase (P450arom) was localized in the interstitial tissue, whereas, under the experimental conditions used, the Sertoli and germ cells did not show any specific staining. In the ovary, the granulosa cells of small follicles exhibited faint immunofluorescent staining for P450arom and the granulosa cells of large, viable more follicles showed a high degree of immunoreactivity. In the corpus luteum, all the luteinized cells showed immunoreactivity. No immunoreactivity was detected in other cells of small and large viable follicles. Immunolocalization of P450arom in the equine testicular Leydig cells and in ovarian granulosa and luteinized cells indicates that these cells have the ability to metabolize androgens to estrogens and possibly to catechol estrogens.

Equine cytochrome P450 aromatase exhibits an estrogen 2-hydroxylase activity in vitro

1996 ◽  
Vol 59 (1) ◽  
pp. 55-61 ◽  
Author(s):  
Jamal Almadhidi ◽  
Safa Moslemi ◽  
Michel A. Drosdowsky ◽  
Gilles-Eric Séralini
Keyword(s):  
Cytochrome P450 ◽  
Hydroxylase Activity ◽  
P450 Aromatase ◽  
Cytochrome P450 Aromatase
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