| 1. |
- Axelsson, Jeanette, et al.
(författare)
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Expression of estrogen receptor-alpha and -beta mRNA in the brain of Japanese quail embryos
- 2007
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Ingår i: Developmental Neurobiology. - : Wiley. - 1932-8451 .- 1932-846X. ; 67:13, s. 1742-1750
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Tidskriftsartikel (refereegranskat)abstract
- The present study was conducted to investigate the mRNA expression of the two estrogen receptor (ER) subtypes ERα and ERβ in the brain of Japanese quail embryos. We found expression of both ERα and ERβ mRNA in homogenate of whole head from 6-day-old embryos, and in brain homogenate from 9- and 12-day-old embryos using real-time PCR. In 9- and 12-day-old embryos the ERα expression was higher in females than in males. We used in situ hybridization to examine the localization of the ERs in sections from male and female brains on day 9 and day 17 of incubation. On day 9, ERβ mRNA was detected in the developing medial preoptic nucleus (POM), in the medial part of the bed nucleus of the striae terminalis (BSTm), and in the tuberal region of the hypothalamus. ERα signal could not be detected in the POM, the BSTm or the tuberal region in 9-day-old embryos. In 17-day-old embryos, ERβ was highly expressed in the preoptic area, the nucleus Taeniae of the Amygdala (TnA) and the BSTm. Expression of ERα mRNA was detected in parts of the preoptic area and in the telencephalic TnA. No ERα expression was found in the BSTm, an area known to be sexually dimorphic in adults. The high embryonic expression of ERβ in brain areas linked to sexual behavior indicates that ERβ plays a role in sexual differentiation of the Japanese quail brain.
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| 2. |
- Bondesson, Maria, et al.
(författare)
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A CASCADE of effects of bisphenol A.
- 2009
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Ingår i: Reproductive Toxicology. - : Elsevier BV. - 0890-6238 .- 1873-1708. ; 28:4, s. 563-7
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Tidskriftsartikel (refereegranskat)
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| 3. |
- Borg, Daniel, et al.
(författare)
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Perinatal tissue distribution of perfluorooctane sulphonate (PFOS) in mice.
- 2009
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Ingår i: Abstracts of the 46th Congress of the European Societies of Toxicology. - : Elsevier BV. ; 189:SI, s. S147-S147
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Konferensbidrag (refereegranskat)abstract
- Perfluorooctane sulfonate (PFOS) is an industrial chemical that has been used as a surfactant and surface protector for more than fifty years. It has during the last decade emerged as an environmental contaminant due to its widespread presence in humans and wildlife and its persistant, bioaccumulative and toxic properties. PFOS is developmentally toxic and late in utero exposure in rodents affects neonatal survival and growth. Observed symptoms suggest impaired pulmonary function, but the cause of the mortality has not been clarified. The purpose of this study was to determine the perinatal tissue distribution of S35-labelled PFOS in mice using whole-body autoradiography (WBA) combined with liquid scintillation counting (LSC). Pregnant C57Bl/6 mice were dosed orally on gestation day (GD) 16 and sampled on GD18, GD20 and postnatal day (PND) 1 (dams + pups). The results from the WBA and the LSC were unequivocal. In dams, PFOS accumulated primarily in the liver, but also the lungs contained levels higher than the blood. PFOS was readily transferred to the fetus. At GD18 general PFOS levels were higher in the fetus than in the blood of the corresponding dam with accumulation in the liver. At GD20, general PFOS levels remained higher in the fetus than in the dam, with substantial accumulation also in the lung. The accumulation in the lung persisted at PND1. Our results show that the fetus is exposed to higher levels of PFOS than the dam and point towards the lung being the main perinatal target organ of PFOS.
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| 4. |
- Brunström, Björn, et al.
(författare)
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Effects of estrogens on sex differentiation in Japanese quail and chicken
- 2009
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Ingår i: General and Comparative Endocrinology. - : Elsevier BV. - 0016-6480 .- 1095-6840. ; 163:1-2, s. 97-103
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Tidskriftsartikel (refereegranskat)abstract
- Estrogen production by the female avian embryo induces development of a female phenotype of the reproductive organs whereas the low estrogen concentration in the male embryo results in a male phenotype. Treatment of female embryos with exogenous estrogens disrupts Müllerian duct development resulting in malformations and impaired oviductal function. Exposure of male embryos to estrogens results in ovotestis formation and persisting Müllerian ducts in the embryos and testicular malformations, reduced semen production and partially developed oviducts in the adult bird. Furthermore, studies in Japanese quail show that the male copulatory behavior is impaired by embryonic estrogen treatment. Results from our experiments with selective agonists for ERalpha and ERbeta suggest that the effects of estrogens on the reproductive organs are mediated via activation of ERalpha. Abundant expression of ERalpha mRNA was shown in gonads and Müllerian ducts of early Japanese quail embryos. Both ERalpha and ERbeta transcripts were detected by real-time PCR in early embryo brains of Japanese quail indicating that both receptors may be involved in sex differentiation of the brain. However, in 9-day-old quail embryo brains in situ hybridization showed expression of ERbeta mRNA, but not of ERalpha mRNA, in the medial preoptic nucleus (POM) and the bed nucleus of the stria terminalis (BSTm), areas implicated in copulatory behavior of adult male quail. Furthermore, embryonic treatment with the selective ERalpha agonist propyl pyrazol triol (PPT) had no effect on the male copulatory behavior. These results suggest that ERbeta may be important for the effects of estrogens on brain differentiation.
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| 5. |
- Danielsson, Conny, et al.
(författare)
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Comparison of Levels of PCDD/Fs and non-Ortho PCBs in PCB 153 from seven different suppliers
- 2008
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Ingår i: Organohalogen Compounds. ; 70, s. 001201-3
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Tidskriftsartikel (refereegranskat)abstract
- Twelve PCBs with dioxin-like (DL) properties have been carefully studied through the years to facilitate risk assessment and they have been assigned WHO-TEF values [1] based on their relative toxicity and endocrine effects compared to 2,3,7,8-TCDD. From a toxicological point of view, the non-dioxin-like PCBs (NDL-PCBs) are less characterized but usually account for more than 90% of the total mass of PCBs in food samples [2]. Furthermore, over 90% of the NDL-PCB exposure in the general population is via food and the average daily intake can be estimated to be 10-45 ng/kg (bw)/day according to the European Food Safety Authority EFSA [3]. The EFSA committee concluded that a proper risk assessment of this abundant and environmentally significant class of compounds could not be accomplished. In 2006, the European Commission initiated a project which has as its aim to better examine the toxicity of NDL-PCBs: ATHON- "Assessing the toxicity and hazard of nondioxin-like PCBs present in food". The ATHON project will perform all in vivo and in vitro studies with ultra pure PCBs with known levels of DL-PCBs, PCDD/Fs and total TEQ-levels. As a first step in this study the major suppliers of PCB 153 were identified and the aim of the research was to investigate if there were any clear differences in the quality of their products based on possible impurities of PCDD/Fs and non-ortho PCBs. PCB 153 was selected because of its relatively high presence in environmental compartments and biota and since it has been the most frequently studied NDL-PCB in a few major in vivo studies [2]. Impurities of PCDD/Fs and DL-PCBs, even at trace levels, in PCB 153 may make a significant contribution to the effects seen in in vivo studies as the highest concentrations being studied are at mg/g (bw)/day during a period of time. These high daily exposure levels in combination with possible accumulation of toxic impurities may by time pose a threat to the significance of observed effects. Within the ATHON project all NDL-PCBs used for both in vitro and in vivo tests are analyzed and in many cases purified to remove possible traces of PCDD/Fs and non-ortho PCBs.
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