Dimorphic expression of testosterone metabolizing enzymes in the hypothalamic area of developing rats

Colciago, Alessandra; Celotti, F.; Pravettoni, A.; Mornati, O.; Martini, L.; Negri‐Cesi, P.

doi:10.1016/j.devbrainres.2004.12.003

Cited by 37 publications

(27 citation statements)

References 40 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The same difference in aromatase levels was also observed in cultured neurons obtained from male or female embryonic hypothalamic areas [19]. Moreover, "in vivo", the enzyme has two male-specific expression peaks, one before (GD 19) and one just after birth (post-natal day (PN) 2) [18]. This finding is consistent with the difference in estradiol content (male > female) recently observed in the hypothalamic/preoptic area of newborn rats within the first 32 h post-partum [20] and strengthen the pivotal role of estradiol in male brain differentiation.…”

Section: The Role Of Estrogenssupporting

confidence: 60%

“…In normal conditions, brain aromatase is expressed only in neurons [15,16] mainly, even though not only, localized in areas involved in the control of the reproductive axis, such as the hypothalamus, the preoptic area and the limbic system [17]. A recent study performed in our laboratory in the developing rat hypothalamus has demonstrated that, during embryogenesis, there is a clear-cut sex difference in aromatase expression, being the enzyme significantly higher in the male than in the female hypothalamus [18]. The same difference in aromatase levels was also observed in cultured neurons obtained from male or female embryonic hypothalamic areas [19].…”

Section: The Role Of Estrogensmentioning

confidence: 98%

See 1 more Smart Citation

Sexual differentiation of the rodent hypothalamus: Hormonal and environmental influences

Negri‐Cesi

Colciago

Pravettoni

et al. 2008

The Journal of Steroid Biochemistry and Molecular Biology

View full text Add to dashboard Cite

Section: The Role Of Estrogenssupporting

confidence: 60%

Section: The Role Of Estrogensmentioning

confidence: 98%

Sexual differentiation of the rodent hypothalamus: Hormonal and environmental influences

Negri‐Cesi

Colciago

Pravettoni

et al. 2008

The Journal of Steroid Biochemistry and Molecular Biology

View full text Add to dashboard Cite

“…Estradiol synthesis occurs in the developing brain at E18.5 and at this time is responsible for sexual imprinting of the brain (44). The present studies reveal expression of a functional ER␤ from E12.5, a time when estradiol is not synthesized in the brain and when the brain is protected from maternal estrogen by its sequestration on alpha-fetoprotein (45).…”

Section: Discussionmentioning

confidence: 63%

Estrogen receptor β expression in the embryonic brain regulates development of calretinin-immunoreactive GABAergic interneurons

Fan

Warner

Gustafsson

2006

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

Our previous studies with estrogen receptor ␤ knockout (ER␤ ؊/؊ ) mice demonstrated that ER␤ is necessary for embryonic development of the brain as early as embryonic day 14.5 (E14.5) and is involved in neuronal migration. Such early effects of ER were unexpected because estradiol synthesis and action in the brain occur at E18.5. In the present study, we examined the distribution of ER␤ in the developing brain and identified a population of ER␤-regulated interneurons. ER␤ appears in the brain at E12.5, mainly localized in the wall of the midbrain, neuromere, hypothalamus, thalamus, and basal plate of pons. At E15.5 and E16.5, ER␤ expression increased in the hypothalamus, thalamus, and midbrain and appeared in the limbic forebrain. At E18.5, ER␤ expression was strongly expressed throughout the brain, including the cerebellum and striatum, whereas there were very few positive cells in the ventricular region. In the paraventricular thalamic nucleus and parafascicular nucleus, most of the calretinin-immunopositive interneurons expressed ER␤. In ER␤ ؊/؊ mice, calretinin expression was markedly lower than in WT mice in the hippocampus, thalamus, and amygdala both at E16.5 and at E18.5. Epidermal growth factor receptor expression was lower in the cortex of ER␤ ؊/؊ than in WT mice at E15.5 and, unlike WT mice, was absent from the superficial marginal zone. These findings suggest that ER␤ in the embryonic brain is necessary for the development of calretininimmunoreactive GABAergic interneurons and for neuronal migration in the cortex through modulating epidermal growth factor receptor expression at middle and later embryonic stages.cortex ͉ EGF receptor ͉ striatum ͉ thalamus E strogen is important during brain development, influencing the maturation of neural systems and affecting the sexual differentiation of brain structures and functions (1, 2). Sexual differentiation in the brain occurs in male rodents at day 18.5 when aromatase is induced in the brain and catalyses the synthesis of estradiol from testosterone secreted from the embryonic testis. At this time, estrogen imprints the neuroendocrine control of gonadal function, reproductive behavior, and the sexual differences in the secretion of growth hormone.Estrogen actions now are recognized to occur via two distinct estrogen receptors (ER), ER␣ and ER␤, that reside in cell nuclei (3, 4). In the brain, ER␣ plays a critical role in regulating reproductive neuroendocrine function, whereas ER␤ may be more important in regulating nonreproductive functions (5-8).In ER␣ knockout mice, no gross brain abnormalities have been reported, whereas ER␤ plays a prominent role during embryogenesis and there are significant morphological abnormalities in the embryonic brains of ER␤ knockout (ER␤ Ϫ/Ϫ ) mice (9). Studies have revealed that ER␤ also is expressed in fetal human brain and may mediate effects of estrogen in the developing nervous system (10). Lemmen et al. (11) reported that ER␤ mRNA is detectable in brains of mouse embryo at embryonic day 10.5 (E10.5), but there is no i...

show abstract

“…PCBs and their metabolites can act at multiple nodes of the neuroendocrine axis: they may serve as hormone mimics (Connor et al, 1997), alter circulating hormone levels (Desaulniers et al, 1999), change patterns of estrous cyclicity (Meerts et al, 2004;Buitenhuis et al, 2004), disrupt hormone metabolism Kester et al, 2000;Yamane et al, 1975), influence endocrine-related and hypothalamic gene expression (Aluru et al, 2004;Bansal et al, 2005;Colciago et al, 2005;Flouriot et al, 1995;Gore et al, 2002;Pravettoni et al, 2005;Salama et al, 2003), interfere with hormone binding proteins (Brouwer and van den Berg, 1986;Chauhan et al, 2000), alter neuronal signaling to endocrine regions of the brain (Khan and Thomas, 2001;Morse et al, 1996;Seegal et al, 1985;Seegal et al, 1990) or indirectly affect steroid receptor availability via molecular crosstalk (Brunnberg et al, 2003;Pearce et al, 2004).…”

mentioning

confidence: 99%

The effects of prenatal PCBs on adult female paced mating reproductive behaviors in rats

Steinberg

Juenger

Gore

2007

Hormones and Behavior

View full text Add to dashboard Cite

Polychlorinated biphenyls (PCBs) are a family of toxicants that persist in measurable quantities in human and wildlife tissues, despite their ban in production in 1977. Some PCB mixtures can act as endocrine disrupting chemicals (EDCs) by mimicking or antagonizing the actions of hormones in the brain and periphery. When exposure to hormonally active substances such as PCBs occurs during vulnerable developmental periods, particularly prenatally or in early postnatal life, they can disrupt sex-specific patterning of the brain, inducing permanent changes that can later be manifested as improper sexual behaviors. Here, we investigated the effects of prenatal exposure to the PCB mixture Aroclor (A) 1221 on adult female reproductive behaviors in a dose-response model in the SpragueDawley rat. Using a paced mating paradigm that permits the female to set the timing of mating and control contact with the male during copulation, we were able to uncover significant differences in female-typical sexual activities in A1221-exposed females. Specifically, A1221 causes significant effects on mating trial pacing, vocalizations, ambulation and the female's likelihood to mate. The results further demonstrate that the intermediate treatment group has the greatest number of disrupted endpoints, suggestive of non-linear dose responses to A1221. These data demonstrate that the behavioral phenotype in adulthood is disrupted by low, ecologically relevant exposures to PCBs, and the results have implications for reproductive success and health in wildlife and women. KeywordsAroclor 1221; Paced mating; PCB; Female reproductive behavior; Endocrine disruption Polychlorinated biphenyls (PCBs) were used in industry as inflammable coolants and lubricants and as components of paints and plastics. Banned in 1977 in response to dawning public awareness of their estrogenic and potentially toxic effects on humans and wildlife, PCBs continue to leach into soil, air and groundwater via retired industrial equipment, and from old factories and buildings. PCBs may have variable degrees of impact depending on which congeners or congener mixtures are involved, the organism's age at exposure, the sex of the individual, the degree of exposure and the availability of compensatory diet or social buffering to counteract those effects. An accurate evaluation of ecologically relevant xenobiotic exposure (Battershill, 1994;Brouwer et al., 1999).The neuroendocrine system serves as an interface between the central nervous system and peripheral endocrine organs, and thus represents a prime target for endocrine disruption by PCBs (Patisaul et al., 2006). PCBs and their metabolites can act at multiple nodes of the neuroendocrine axis: they may serve as hormone mimics (Connor et al., 1997), alter circulating hormone levels (Desaulniers et al., 1999), change patterns of estrous cyclicity (Meerts et al., 2004;Buitenhuis et al., 2004), disrupt hormone metabolism Kester et al., 2000;Yamane et al., 1975), influence endocrine-related and hypothalamic gene expression ...

show abstract

Dimorphic expression of testosterone metabolizing enzymes in the hypothalamic area of developing rats

Cited by 37 publications

References 40 publications

Sexual differentiation of the rodent hypothalamus: Hormonal and environmental influences

Sexual differentiation of the rodent hypothalamus: Hormonal and environmental influences

Estrogen receptor β expression in the embryonic brain regulates development of calretinin-immunoreactive GABAergic interneurons

The effects of prenatal PCBs on adult female paced mating reproductive behaviors in rats

Contact Info

Product

Resources

About