Estrogen receptor mRNA levels in the preoptic area of neonatal rats are responsive to hormone manipulation

DonCarlos, Lydia L.; McAbee, Michael D.; Ramer-Quinn, D S; Stancik, D.M.

doi:10.1016/0165-3806(94)00179-4

Cited by 70 publications

(45 citation statements)

References 23 publications

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“…This seemingly conflicts with a report that neonatal castration does not significantly increase ER α immunoreactivity in the prairie vole mPOA (Cushing and Kramer, 2005), and could indicate that the source of relevant testosterone is not from the testes. Our results are consistent with data from rats demonstrating that sex differences in ER α expression in the mPOA can be eliminated by neonatal castration (DonCarlos et al, 1995;Kuhnemann et al, 1995;Orikasa et al, 1996). Interestingly, sexual differentiation of this system may proceed via a different mechanism in mice, as aromatase knock-out males have fewer ER α -immunoreactive cells in the mPOA than wild-type males (Kudwa et al, 2007).…”

Section: Role Of Aromatase In Th and Er α Expressionsupporting

confidence: 91%

Sex differences and effects of neonatal aromatase inhibition on masculine and feminine copulatory potentials in prairie voles

Northcutt

Lonstein

2008

Hormones and Behavior

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Copulatory behaviors in most rodents are highly sexually dimorphic, even when circulating hormones are equated between the sexes. Prairie voles (Microtus ochrogaster) are monomorphic in their display of some social behaviors, including partner preferences and parenting, but differences between the sexes in their masculine and feminine copulatory behavior potentials have not been studied in detail. Furthermore, the role of neonatal aromatization of testosterone to estradiol on the development of prairie vole sexual behavior potentials or their brain is unknown. To address these issues, prairie vole pups were injected daily for the first week after birth with 0.5 mg of the aromatase inhibitor 1,4,6-androstatriene-3,17-dione (ATD) or oil. Masculine and feminine copulatory behaviors in response to testosterone or estradiol were later examined in both sexes. Males and females showed high mounting and thrusting in response to testosterone, but only males reliably showed ejaculatory behavior. Conversely, males never showed feminine copulatory behaviors in response to estradiol. Sex differences in these behaviors were not affected by neonatal ATD, but ATD-treated females received fewer mounts and thrusts than controls, possibly indicating reduced attractiveness to males. In other groups of subjects, neonatal ATD demasculinized males' tyrosine hydroxylase expression in the anteroventral periventricular preoptic area, and estrogen receptor alpha expression in the medial preoptic area. Thus, although sexual behavior in both sexes of prairie voles is highly masculinized, aromatase during neonatal life is necessary only for females' femininity. Furthermore, copulatory behavior potentials and brain development in male prairie voles are dissociable by their requirement for neonatal aromatase. Keywordsaromatase; estradiol; Microtus; neonatal; sexual behavior; sexual differentiation; voles Masculine and feminine copulatory behaviors are highly sexually dimorphic in many rodent species, even when levels of steroid hormones are equated in adult males and females (see Wallen and Baum, 2002). Indeed, treating male rats or mice with ovarian hormones rarely results in high levels of feminine sexual behaviors (Dominguez-Salazar et al., 2002;Edwards and Burge, 1971;Kudwa et al., 2005;Parsons et al., 1984;Whalen et al., 1986;Whalen and Olsen, 1981). Furthermore, although female rats treated with testosterone may mount other females, the frequency is often low compared to males, and intromissive and ejaculatory behaviors are rarely displayed in either rats or mice given testosterone Dominguez-Salazar et al., 2002;Edwards and Burge, 1971;Gladue and Clemens, 1980;Levine and Mullins, 1964;Whalen and Olsen, 1981). 108 Giltner Hall, Michigan State University, East Lansing, MI 48824, Phone: (517) FAX: (517) 432-2744, northcu2@msu.edu . Prairie voles (Microtus ochrogaster) are an interesting species to study sex differences in behavioral potentials because they are relatively monomorphic in some of their social behaviors, as both se...

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Section: Role Of Aromatase In Th and Er α Expressionsupporting

confidence: 91%

Sex differences and effects of neonatal aromatase inhibition on masculine and feminine copulatory potentials in prairie voles

Northcutt

Lonstein

2008

Hormones and Behavior

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“…ER levels were already lowered partly in the mPOA and almost completely in the Arc. In support of the role of neonatal estrogen in the sexual differentiation of ER in the preoptic area are the findings of DonCarlos et al 25 Female rats neonatally treated with the synthetic estrogen, diethylstilbestrol, showed at the age of 28 days reduced ER mRNA levels in the preoptic area, comparable to the levels seen in intact males. The non-aromatizable androgen, dihydrotestosterone, had no effect on ER mRNA in the preoptic area of females.…”

Section: Estrogen Receptor Immunoreactivitymentioning

confidence: 69%

Quantitative estimation of estrogen and androgen receptor-immunoreactive cells in the forebrain of neonatally estrogen-deprived male rats

et al. 1997

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Abstract--Using quantitative immunocytochemical procedures, the total number of estrogen and androgen receptors was estimated in a large number of hypothalamic and limbic nuclei of male rats, in which brain estrogen formation was inhibited neonatally by treatment with the aromatase inhibitor 1,4,6-androstatriene-3,17-dione. The highest densities of estrogen receptor immunoreactivity were observed in the periventricular preoptic area and the medial preoptic area. Neonatally estrogen-deprived males showed a higher estrogen receptor immunoreactivity than control males in the periventricular preoptic area and the ventrolateral portion of the ventromedial nucleus of the hypothalamus, i.e. those brain areas in which sex differences have been reported, with female rats showing a greater estrogen binding capacity than male rats. The highest densities of androgen receptor immunoreactivity were found in the septohypothalamic nucleus, the medial preoptic area, the posterior division of the bed nucleus of the stria terminalis and the posterodorsal division of the medial amygdaloid nucleus. No significant differences in distribution or total numbers of androgen receptors were found between neonatally estrogen-deprived males and control males.These findings suggest that neonatal estrogens, derived from the neural aromatization of testosterone, are involved in the sexual differentiation of the estrogen receptor system in the periventricular preoptic area and the ventromedial hypothalamus. The role of neonatal estrogens in the development of the forebrain androgen receptor system is less clear. 1997 IBRO. Published by Elsevier Science Ltd.Key words: neonatal ATD treatment, androgen receptor, estrogen receptor, estrogens, hypothalamus, preoptic area.In mammals, testosterone and estradiol derived from neural aromatization of testosterone act synergistically in the developing male brain to organize its structures and functions, i.e. to masculinize and defeminize the neural substrates that later control sexual behavior and neuroendocrine function. In the rat brain, masculinization results in the display of male-typical sexual behavior (mounts, intromissions and ejaculations) in adulthood. Defeminization results in a loss of cyclic release of gonadotropins necessary for ovulation and a loss of female-typical sexual behavior (lordosis, presenting, ear wiggling, hop and dart) in adulthood (e.g., Ref. 37). Thus, gonadally intact male rats display the complete pattern of male coital behavior when pair tested with an estrous female and no female-typical sexual behavior when pair tested with a sexually active male. However, lordosis behavior can be induced in castrated male rats by administering estradiol and progesterone, although the behavior displayed is usually less intense than that of females, and considerably more estradiol is required for its stimulation. 20,42,54 The development of the female rat brain is generally believed to proceed in the absence of testosterone and estradiol. Gonadally intact female rats display periods of be...

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“…The hypothalamus of the female has a higher ER density and mRNA expression than that of the male [16, 17, 18]. Estrogen treatment during the peri- or postnatal period results in a decrease in ERs [15, 16, 17, 18, 44]. The downregulation of ER mRNA may be an important estrogen-regulated event in the process of brain sexual differentiation [15, 16, 17, 18].…”

Section: Discussionmentioning

confidence: 99%

“…ER concentration represents an important component of the mechanism of sexual differentiation in the brain [2, 14]. Recently, numerous studies have demonstrated that the simultaneous expression of brain ERs and aromatase during pre- and postnatal ontogeny plays a potential role in brain differentiation in mammals [1, 12, 15, 16, 17, 18]. However, little is known of the mRNA expression by brain aromatase and ERs during the critical period of sexual differentiation.…”

Section: Introductionmentioning

confidence: 99%

Estradiol and <i>para</i>-Chlorophenylalanine Downregulate the Expression of Brain Aromatase and Estrogen Receptor-α mRNA during the Critical Period of Feminization in Tilapia <i>(Oreochromis mossambicus)</i>

2001

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The period of maximal feminizing action of 17β-estradiol (E₂) upon sex ratio is before 10 days posthatching in tilapia (Oreochromis mossambicus). The effect of E₂ at this time is mimicked by para-chlorophenylalanine (p-CPA), a serotonin (5-hydroxytryptamine; 5-HT) synthesis inhibitor. The effect of E₂ on sexual differentiation may be mediated by the 5-HT system, which is consistent with the suggestion in mammals. The masculinizing actions of 17α-methyltestosterone (MT) are most potent later at up to day 20 of age, and may depend on MT induction of aromatase activity. In the present study, the effects of gonadal steroids and p-CPA on brain aromatase and estrogen receptor (ER) mRNA expression during the critical period of sexual differentiation were investigated. Treatment of tilapia with E₂ resulted in a significant decrease in the expression of brain aromatase and ERα between days 0 and 10, but not subsequently. The effect of E₂ at this time can be mimicked by p-CPA. Treatment of tilapia with MT, by contrast, resulted in a significant increase in brain aromatase, ERα and ERβ mRNA expression when given between days 10 and 20. The downregulation of brain aromatase and ERα mRNA expression by E₂ before 10 days of age and, in turn, the upregulation of brain aromatase and ERα and ERβ mRNA expression by MT at up to day 20 of age coincide with the period in which E₂ and MT have the maximal effect on gonadal feminization and masculinization, respectively.

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Estrogen receptor mRNA levels in the preoptic area of neonatal rats are responsive to hormone manipulation

Cited by 70 publications

References 23 publications

Sex differences and effects of neonatal aromatase inhibition on masculine and feminine copulatory potentials in prairie voles

Sex differences and effects of neonatal aromatase inhibition on masculine and feminine copulatory potentials in prairie voles

Quantitative estimation of estrogen and androgen receptor-immunoreactive cells in the forebrain of neonatally estrogen-deprived male rats

Estradiol and <i>para</i>-Chlorophenylalanine Downregulate the Expression of Brain Aromatase and Estrogen Receptor-α mRNA during the Critical Period of Feminization in Tilapia <i>(Oreochromis mossambicus)</i>

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