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Papers by Clarisa Santamaría

Research paper thumbnail of Characterization of Oct4-GFP transgenic mice as a model to study the effect of environmental estrogens on the maturation of male germ cells by using flow cytometry

The Journal of Steroid Biochemistry and Molecular Biology, 2015

Oct4 is involved in regulation of pluripotency during normal development and is down-regulated du... more Oct4 is involved in regulation of pluripotency during normal development and is down-regulated during formation of postnatal reservoir of germ cells. We propose thatOct4/GFP transgenic mouse, which mimics the endogenous expression pattern of Oct4, could be used as a mammalian model to study the effects of environmental estrogens on the development of male germ cells. Oct4/GFP maturation profile was assessed during postnatal days -PND- 3, 5, 7, 10, 14 and 80, using flow cytometry. Then, we exposed pregnant mothers to 17α-ethinylestradiol (EE2) from day post coitum (dpc) 5 to PND7. Percentage of Oct4/GFP-expressing cells and levels of expression of Oct4/GPF were increased in PND7 after EE2 exposure. These observations were confirmed by analysis of GFP and endogenous Oct4 protein in the seminiferous tubules and by a reduction in epididymal sperm count in adult mice. We introduced Oct4/GFP mouse together with flow cytometry as a tool to evaluate changes in male germ cells development.

Research paper thumbnail of Ovarian dysfunctions in adult female rat offspring born to mothers perinatally exposed to low doses of bisphenol A

The Journal of steroid biochemistry and molecular biology, Jan 4, 2015

The study of oral exposure to the environmental estrogen bisphenol A (BPA) during the perinatal p... more The study of oral exposure to the environmental estrogen bisphenol A (BPA) during the perinatal period and its effects on ovarian functionality in adulthood has generated special interest. Thus, our objective was to investigate ovarian folliculogenesis and steroidogenesis in adult female rat offspring born to mothers exposed to low doses of BPA (BPA50: 50μg/kgday; BPA0.5: 0.5μg/kgday) by the oral route during gestation and breastfeeding. Ovaries from both BPA-treated groups showed reduced primordial follicle recruitment and a greater number of corpora lutea, indicating an increased number of ovulated oocytes, coupled with higher levels of mRNA expression of 3β-hydroxysteroid dehydrogenase and serum progesterone. BPA50-treated animals had lower expression of androgen receptor (AR) at different stages of the growing follicle population. BPA0.5-treated rats evidenced an imbalance of AR expression between primordial/primary follicles, with higher mRNA-follicle-stimulating hormone recept...

Research paper thumbnail of Characterization of Oct4-GFP transgenic mice as a model to study the effect of environmental estrogens on the maturation of male germ cells by using flow cytometry

The Journal of Steroid Biochemistry and Molecular Biology, 2015

Oct4 is involved in regulation of pluripotency during normal development and is down-regulated du... more Oct4 is involved in regulation of pluripotency during normal development and is down-regulated during formation of postnatal reservoir of germ cells. We propose thatOct4/GFP transgenic mouse, which mimics the endogenous expression pattern of Oct4, could be used as a mammalian model to study the effects of environmental estrogens on the development of male germ cells. Oct4/GFP maturation profile was assessed during postnatal days -PND- 3, 5, 7, 10, 14 and 80, using flow cytometry. Then, we exposed pregnant mothers to 17α-ethinylestradiol (EE2) from day post coitum (dpc) 5 to PND7. Percentage of Oct4/GFP-expressing cells and levels of expression of Oct4/GPF were increased in PND7 after EE2 exposure. These observations were confirmed by analysis of GFP and endogenous Oct4 protein in the seminiferous tubules and by a reduction in epididymal sperm count in adult mice. We introduced Oct4/GFP mouse together with flow cytometry as a tool to evaluate changes in male germ cells development.

Research paper thumbnail of Neonatal exposure to bisphenol A reduces the pool of primordial follicles in the rat ovary

Reproductive Toxicology, 2010

We evaluated whether exposure to bisphenol A (BPA) disrupts neonatal follicle development in rats... more We evaluated whether exposure to bisphenol A (BPA) disrupts neonatal follicle development in rats. From postnatal day 1 (PND1) to PND7, pups received corn oil (control), diethylstilbestrol (DES20: 20 g/kgd, DES0.2: 0.2 g/kg-d), or BPA (BPA20: 20 mg/kg-d, BPA0.05: 0.05 mg/kg-d). We examined follicular dynamics, multioocyte follicles (MOFs) incidence, proliferation and apoptosis rates, expression of steroid receptors (ER␣, ER␤, PR, AR) and cyclin-dependent kinase inhibitor 1B (p27) in PND8 ovaries. DES20, DES0.2 and BPA20-ovaries showed fewer primordial follicles and increased growing follicles. DES20ovaries exhibited increased incidence of MOFs. Oocyte survival, AR, PR and apoptosis were not changed. Primordial and recruited follicles from BPA20-ovaries showed higher p27, whereas ER␤ and proliferation were both increased in recruited follicles. ER␣ positive primary follicles increased in BPA 20-ovaries. Results show that BPA reduces the primordial follicle pool by stimulating the neonatal initial recruitment, associated with an increased proliferation rate likely mediated by an estrogenic pathway.

Research paper thumbnail of Neonatal exposure to xenoestrogens impairs the ovarian response to gonadotropin treatment in lambs

Reproduction (Cambridge, England), Jan 16, 2015

Bisphenol A (BPA) and diethylstilbestrol (DES) are xenoestrogens which have been associated with ... more Bisphenol A (BPA) and diethylstilbestrol (DES) are xenoestrogens which have been associated with altered effects on reproduction. We hypothesized that neonatal xenoestrogen exposure affects the ovarian functionality in lambs. Thus, we evaluated the ovarian response to exogenous ovine Follicle Stimulating Hormone (oFSH) administered from postnatal day 30 (PND30) to PND32 in female lambs previously exposed to low doses of DES or BPA (BPA50: 50 μg/kg.day, BPA0.5: 0.5 μg/kg.day) from PND1 to PND14. We determined: a) follicular growth, b) circulating levels of E2, c) steroid receptors (ERA, ERB, AR) and atresia, d) mRNA expression levels of the ovarian bone morphogenetic protein (BMPs) system (BMP6, BMP15, BMP receptor type 1B, GDF9) and FSH receptor (FSHR). Lambs neonatally exposed to DES or BPA showed an impaired ovarian response to oFSH with a lower number of follicles ≥2 mm together with a lower number of atretic follicles and no increase in E2 serum levels in response to oFSH treatm...

Research paper thumbnail of Characterization of Oct4-GFP transgenic mice as a model to study the effect of environmental estrogens on the maturation of male germ cells by using flow cytometry

The Journal of Steroid Biochemistry and Molecular Biology, 2015

Oct4 is involved in regulation of pluripotency during normal development and is down-regulated du... more Oct4 is involved in regulation of pluripotency during normal development and is down-regulated during formation of postnatal reservoir of germ cells. We propose thatOct4/GFP transgenic mouse, which mimics the endogenous expression pattern of Oct4, could be used as a mammalian model to study the effects of environmental estrogens on the development of male germ cells. Oct4/GFP maturation profile was assessed during postnatal days -PND- 3, 5, 7, 10, 14 and 80, using flow cytometry. Then, we exposed pregnant mothers to 17α-ethinylestradiol (EE2) from day post coitum (dpc) 5 to PND7. Percentage of Oct4/GFP-expressing cells and levels of expression of Oct4/GPF were increased in PND7 after EE2 exposure. These observations were confirmed by analysis of GFP and endogenous Oct4 protein in the seminiferous tubules and by a reduction in epididymal sperm count in adult mice. We introduced Oct4/GFP mouse together with flow cytometry as a tool to evaluate changes in male germ cells development.

Research paper thumbnail of Ovarian dysfunctions in adult female rat offspring born to mothers perinatally exposed to low doses of bisphenol A

The Journal of steroid biochemistry and molecular biology, Jan 4, 2015

The study of oral exposure to the environmental estrogen bisphenol A (BPA) during the perinatal p... more The study of oral exposure to the environmental estrogen bisphenol A (BPA) during the perinatal period and its effects on ovarian functionality in adulthood has generated special interest. Thus, our objective was to investigate ovarian folliculogenesis and steroidogenesis in adult female rat offspring born to mothers exposed to low doses of BPA (BPA50: 50μg/kgday; BPA0.5: 0.5μg/kgday) by the oral route during gestation and breastfeeding. Ovaries from both BPA-treated groups showed reduced primordial follicle recruitment and a greater number of corpora lutea, indicating an increased number of ovulated oocytes, coupled with higher levels of mRNA expression of 3β-hydroxysteroid dehydrogenase and serum progesterone. BPA50-treated animals had lower expression of androgen receptor (AR) at different stages of the growing follicle population. BPA0.5-treated rats evidenced an imbalance of AR expression between primordial/primary follicles, with higher mRNA-follicle-stimulating hormone recept...

Research paper thumbnail of Characterization of Oct4-GFP transgenic mice as a model to study the effect of environmental estrogens on the maturation of male germ cells by using flow cytometry

The Journal of Steroid Biochemistry and Molecular Biology, 2015

Oct4 is involved in regulation of pluripotency during normal development and is down-regulated du... more Oct4 is involved in regulation of pluripotency during normal development and is down-regulated during formation of postnatal reservoir of germ cells. We propose thatOct4/GFP transgenic mouse, which mimics the endogenous expression pattern of Oct4, could be used as a mammalian model to study the effects of environmental estrogens on the development of male germ cells. Oct4/GFP maturation profile was assessed during postnatal days -PND- 3, 5, 7, 10, 14 and 80, using flow cytometry. Then, we exposed pregnant mothers to 17α-ethinylestradiol (EE2) from day post coitum (dpc) 5 to PND7. Percentage of Oct4/GFP-expressing cells and levels of expression of Oct4/GPF were increased in PND7 after EE2 exposure. These observations were confirmed by analysis of GFP and endogenous Oct4 protein in the seminiferous tubules and by a reduction in epididymal sperm count in adult mice. We introduced Oct4/GFP mouse together with flow cytometry as a tool to evaluate changes in male germ cells development.

Research paper thumbnail of Neonatal exposure to bisphenol A reduces the pool of primordial follicles in the rat ovary

Reproductive Toxicology, 2010

We evaluated whether exposure to bisphenol A (BPA) disrupts neonatal follicle development in rats... more We evaluated whether exposure to bisphenol A (BPA) disrupts neonatal follicle development in rats. From postnatal day 1 (PND1) to PND7, pups received corn oil (control), diethylstilbestrol (DES20: 20 g/kgd, DES0.2: 0.2 g/kg-d), or BPA (BPA20: 20 mg/kg-d, BPA0.05: 0.05 mg/kg-d). We examined follicular dynamics, multioocyte follicles (MOFs) incidence, proliferation and apoptosis rates, expression of steroid receptors (ER␣, ER␤, PR, AR) and cyclin-dependent kinase inhibitor 1B (p27) in PND8 ovaries. DES20, DES0.2 and BPA20-ovaries showed fewer primordial follicles and increased growing follicles. DES20ovaries exhibited increased incidence of MOFs. Oocyte survival, AR, PR and apoptosis were not changed. Primordial and recruited follicles from BPA20-ovaries showed higher p27, whereas ER␤ and proliferation were both increased in recruited follicles. ER␣ positive primary follicles increased in BPA 20-ovaries. Results show that BPA reduces the primordial follicle pool by stimulating the neonatal initial recruitment, associated with an increased proliferation rate likely mediated by an estrogenic pathway.

Research paper thumbnail of Neonatal exposure to xenoestrogens impairs the ovarian response to gonadotropin treatment in lambs

Reproduction (Cambridge, England), Jan 16, 2015

Bisphenol A (BPA) and diethylstilbestrol (DES) are xenoestrogens which have been associated with ... more Bisphenol A (BPA) and diethylstilbestrol (DES) are xenoestrogens which have been associated with altered effects on reproduction. We hypothesized that neonatal xenoestrogen exposure affects the ovarian functionality in lambs. Thus, we evaluated the ovarian response to exogenous ovine Follicle Stimulating Hormone (oFSH) administered from postnatal day 30 (PND30) to PND32 in female lambs previously exposed to low doses of DES or BPA (BPA50: 50 μg/kg.day, BPA0.5: 0.5 μg/kg.day) from PND1 to PND14. We determined: a) follicular growth, b) circulating levels of E2, c) steroid receptors (ERA, ERB, AR) and atresia, d) mRNA expression levels of the ovarian bone morphogenetic protein (BMPs) system (BMP6, BMP15, BMP receptor type 1B, GDF9) and FSH receptor (FSHR). Lambs neonatally exposed to DES or BPA showed an impaired ovarian response to oFSH with a lower number of follicles ≥2 mm together with a lower number of atretic follicles and no increase in E2 serum levels in response to oFSH treatm...