Estrogen metabolites in equine ovarian follicles: Gas chromatographic-mass spectrometric determinations in relation to follicular ultrastructure and progestin content

Silberzahn, Pierre; Almahbobi, Ghanim; Dehennin, L.; Merouane, Abdelaziz

doi:10.1016/0022-4731(85)90169-4

Cited by 39 publications

(18 citation statements)

References 17 publications

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“…This is in agreement with the fact that the estrogen levels greatly increase in follicular fluid from small to large viable follicles and decrease during the pre-ovulatory phase (8,29). Moreover, equine granulosa cells of viable follicles possess a very active aromatizing system (38.58).…”

Section: Discussionsupporting

confidence: 85%

“…In mare, the concentration of estradiol-l7fl, which is the main estrogen in the follicular fluid, is greatly increased in the large follicles compared with the small follicles (8,29). The mare cyclic corpus luteum aromatizes androgens very efficiently (30), although only low levels of circulating estradioL17fl are present during the luteal phase (31,32).…”

Section: Introductionmentioning

confidence: 99%

“…Estrogen biosynthesis occurs in several tissues and cells of mammals, including adipose tissue, skin fibroblasts, brain, pituitary, prostate, testis, ovary, placenta, and retina (3)(4)(5)(6)(7)(8)(9)(10). P450arom has been immunohistochemically localized in the syncytiotrophoblast of the human placenta (11)(12)(13)(14)(15), in ovaries of human, rat, mice, golden hamster, guinea pig, and cow (11,14,(16)(17)(18)(19)(20)(21)(22), in testes of rat, mouse, Supported in part by a grant from the Association pour la Recherche sur le Cancer (grant no.…”

Section: Introductionmentioning

confidence: 99%

“…6933) and by a grant from the Ligue Nationale Fransaise contre le Cancer (Comitt de la Manche). and bear (23)(24)(25), in human prostate (6), in the brain of quail, rat, and mouse (26-28), and in the retina of goldfish (10).In mare, the concentration of estradiol-l7fl, which is the main estrogen in the follicular fluid, is greatly increased in the large follicles compared with the small follicles (8,29). The mare cyclic corpus luteum aromatizes androgens very efficiently (30), although only low levels of circulating estradioL17fl are present during the luteal phase (31,32).…”

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confidence: 99%

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Immunohistochemical localization of cytochrome P450 aromatase in equine gonads.

Almadhidi

Seralini²,

Fresnel³

et al. 1995

J Histochem Cytochem.

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Estrogens are the major steroids produced by equine gonads.To identrfy 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, immuneblot analysis, and immunoneutralization studies. Immunofluorescence microscopy demonstrated that in the male gonad, cytochrome P450 aromtase (P45Oamm) 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 IntroductionThe conversion of androgens to estrogens, termed aromatization, is catalyzed by P45Oarom enzyme, the product of the gene called CYP19 in humans (1). Recently, Osawa et al. (2) showed that aromatase also acts as estrogen 2-hydroxylase and postulated that this enzyme could be responsible for the high levels of catechol estrogens and 19-hydroxyandrogens during pregnancy. The enzymatic complex, which is located in the endoplasmic reticulum, includes the heme glycoprotein P450arom and the flavoprotein NADPH-cytochrome P450 reductase.Estrogen biosynthesis occurs in several tissues and cells of mammals, including adipose tissue, skin fibroblasts, brain, pituitary, prostate, testis, ovary, placenta, and retina (3-10). P450arom has been immunohistochemically localized in the syncytiotrophoblast of the human placenta (11)(12)(13)(14)(15), in ovaries of human, rat, mice, golden hamster, guinea pig, and cow (11,14,(16)(17)(18)(19)(20)(21)(22), in testes of rat, mouse, Supported in part by a grant from the Association pour la Recherche sur le Cancer (grant no. 6933) and by a grant from the Ligue Nationale Fransaise contre le Cancer (Comitt de la Manche). and bear (23)(24)(25), in human prostate (6), in the brain of quail, rat, and mouse (26-28), and in the retina of goldfish (10).In mare, the concentration of estradiol-l7fl, which is the main estrogen in the follicular fluid, is greatly increased in the large follicles compared with the small follicles (8,29). The mare cyclic corpus luteum aromatizes androgens very efficiently (30), although only low levels of circulating estradioL17fl are present during the luteal phase (31,32). In comparison to other species (33,34), the stallion testis secretes very high amounts of estrogens, essentially as estrogen-3-sulfates. Plasma estrogens markedly increase with age (35), together with the number and volume of Leydig cells (36). However, the cellular localization of aromatase has not yet been established in equine ovary and testis.We have previously shown that equine aromatase exhibits some distinct properties compared with the human enzyme: the equine testicular, placental, and ovarian estrogen synthetase aromatizes androgens and 19-norandrogens with similar velocity, but not 16a-hydroxytestosterone or epitestosterone, in contrast to the human placental enzyme, which aromatizes androg...

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Section: Discussionsupporting

confidence: 85%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 99%

See 2 more Smart Citations

Immunohistochemical localization of cytochrome P450 aromatase in equine gonads.

Almadhidi

Seralini²,

Fresnel³

et al. 1995

J Histochem Cytochem.

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“…As BMPs normally cause decreased progesterone production (Shimasaki et al 1999(Shimasaki et al , 2004), it appears that reduced BMP signaling in Booroola ewes underlies the increased levels of progesterone, and FSH therefore promoting follicular maturation and ultimately rate of ovulation observed in this study. In previous study we (G A) have demonstrated that ultrastructural luteinisation of granulosa cells of preovulatory follicles in mares coincides with elevation of progesterone production (Silberzahn et al 1985).…”

Section: Discussionmentioning

confidence: 99%

Ovarian follicle development in Booroola sheep exhibiting impaired bone morphogenetic protein signalling pathway

Ruoss¹,

Tadros²,

O’Shea³

et al. 2009

Reproduction

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The role of bone morphogenetic proteins (BMPs) in the regulation of ovarian function has been extensively investigated but the mechanism of regulation is not well understood. The aim of this study was to investigate the effect of mutation in the BMP receptor in Booroola sheep on the number of primordial follicles and rate of follicle recruitment in comparison with that in normal merino sheep in vivo. Whole sheep ovaries at the time of birth, 1.5 and 5 years old were collected and processed for the follicle quantification, using computerised stereological methods and statistical analyses. At birth, the total number of primordial follicles in Booroola sheep was significantly lower than in merino sheep. At 1.5 and 5 years, a reversed pattern in favour of Booroola ewes was seen with significantly more primordial follicles than merino. In parallel, the rate of primordial follicle recruitment to developing cohort was substantially lower in Booroola ewes with only 51 and 66% of primordial follicle consumption at 1.5 and 5 years respectively compared to 92 and 97% in merino ewes. On other hand, the mean numbers of developing primary follicles were smaller in Booroola sheep at the time of birth, yet, Booroola ewes possess more primary follicles than merino at 1.5 years. These findings suggest that attenuation of the intraovarian signalling pathway of BMPs may in fact be a successful means of rationalising follicle consumption, preventing unnecessary loss of follicles from the initial primordial follicle pool, hence increasing reproductive longevity and fertility.

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Changes in the gene expression pattern induced by 2-methoxyestradiol in the mouse uterus

et al. 2013

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2-Methoxyestradiol (2ME) is an estrogen metabolite with antitumor and antiangiogenic properties, although their effects on the reproductive tissues are not well-determined. Furthermore, it is not very clear whether 2ME is part of the intracellular signaling of estradiol (E2) or it acts through other signaling pathways. The purpose of this study was to determine changes in the gene expression pattern in the mouse female reproductive tract induced by 2ME, under conditions in which this metabolite has no estrogenic activity. Therefore, we first compared the effect of 2ME or E2 on the uterine weight and epithelial cell height, and on the ovarian weight and the number of follicles of immature mice. Then, we examined the gene expression profile in the uterus of immature mice treated with 2ME or E2 and we selected three genes scd2, snx6, and spon1, to confirm differential regulation by E2 and 2ME in the uterine cells using real-time PCR. Finally, in order to explore the physiologic relevance of the 2ME-induced genes we determined the expression and localization of the F-spondin protein encoded by spon1 in the uterus of mature mice treated with E2 or 2ME. Estradiol and 2ME reduced the ovarian weight and decreased the number of follicles ≥ 300 μm, whereas E2 increased the uterine weight and epithelial cell height but not 2ME, indicating that 2ME did not have estrogenic activity in the mouse uterus. Microarray analysis showed that 1.8 % of the uterine genes were regulated by E2 and 0.23 % by 2ME, while 0.04 % was regulated by E2 and 2ME. The mRNA for scd2 was exclusively increased by 2ME, whereas snx6 and spon1 were up-regulated by E2 and 2ME, but the response to 2ME was more intense. F-spondin was mainly expressed in the uterine stroma layer although 2ME or E2 did not change its localization in the uterine cells. We conclude that 2ME regulates a group of genes in the mice uterus, independently of estrogenic activity, suggesting a functional involvement of 2ME in the mammalian uterus.

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Estrogen metabolites in equine ovarian follicles: Gas chromatographic-mass spectrometric determinations in relation to follicular ultrastructure and progestin content

Cited by 39 publications

References 17 publications

Immunohistochemical localization of cytochrome P450 aromatase in equine gonads.

Immunohistochemical localization of cytochrome P450 aromatase in equine gonads.

Ovarian follicle development in Booroola sheep exhibiting impaired bone morphogenetic protein signalling pathway

Changes in the gene expression pattern induced by 2-methoxyestradiol in the mouse uterus

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