Influence of Ovariectomy and Ovarian Steroids on Hypothalamic Tyrosine Hydroxylase Activity in the Rat13

Beattie, Craig W.; Rodgers, Charles H.; Soyka, Lester F.

doi:10.1210/endo-91-1-276

Cited by 106 publications

(39 citation statements)

References 16 publications

(18 reference statements)

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“…An extension of this study was to determine whether the putative contacts between GnRH neurons and TIDA neurons involve DA neurons containing estrogen receptor alpha (ERα). This study was prompted by numerous reports indicating a role for circulating ovarian hormones on TH activity in the hypothalamus [21, 22, 23, 24, 25, 26, 27]. …”

Section: Introductionmentioning

confidence: 99%

A Confocal Microscopic Study of Gonadotropin-Releasing Hormone (GnRH) Neuron Inputs to Dopaminergic Neurons Containing Estrogen Receptor α in the Arcuate Nucleus of GnRH-Green Fluorescent Protein Transgenic Mice

et al. 2003

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The purpose of the present study was to determine whether the septo-preoptico-tuberoinfundibular gonadotropin-releasing hormone (GnRH) pathway comes in close juxtaposition with tyrosine hydroxylase immunoreactive (TH-IR) neurons in the arcuate nucleus of female mice. Immunohistochemical staining with a TH monoclonal antibody coupled with confocal microscopy was employed on vibratome-cut brain sections of female GnRH-green fluorescent protein (GFP) transgenic mice to evaluate possible appositions between GnRH and tuberoinfundibular dopaminergic (TIDA) neurons. TH-IR neurons of the arcuate nucleus received GnRH neuronal appositions in adult female mice at proestrus and estrus stages. In contrast, no GnRH appositions were observed in adult females at diestrus. Subsequently, double immunohistochemical staining for TH and estrogen receptor-α (ERα) was performed to examine the role of estradiol on this relationship. We found that most TH-IR neurons contacted by GnRH fibers were immunoreactive for ERα. Our observations suggest that GnRH neurons communicate directly with TIDA neurons in the adult female. Furthermore, ERα activation in TIDA neurons may be involved in the formation of connections between GnRH neurons and TIDA neurons.

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Section: Introductionmentioning

confidence: 99%

A Confocal Microscopic Study of Gonadotropin-Releasing Hormone (GnRH) Neuron Inputs to Dopaminergic Neurons Containing Estrogen Receptor α in the Arcuate Nucleus of GnRH-Green Fluorescent Protein Transgenic Mice

et al. 2003

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“…Progesterone reduces TH activity in hypothalamic fragments from ovariectomized and estradiol-treated ovariectomized rats [9]. A similar decrease in 3,4-dihydroxyphenylacetic acid (DOPAC) concentrations in the median eminence occurs within 5 h of progesterone treatment in estradiol-treated, but not in untreated ovariectomized rats [4].…”

Section: Introductionmentioning

confidence: 99%

Progesterone Induces Dephosphorylation and Inactivation of Tyrosine Hydroxylase in Rat Hypothalamic Dopaminergic Neurons

Arbogast

Voogt²

2002

Neuroendocrinology

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After in vivo treatment, progesterone initially decreases tyrosine hydroxylase (TH) activity in the TIDA neurons, but subsequently increases TH activity with prolonged treatment. In order to explore the cellular mechanism for progesterone’s effect, this study examined the acute inhibitory action of progesterone on TH activity in rat fetal hypothalamic dopaminergic neurons in vitro. Progesterone caused a rapid decrease in TH activity within 1 h, which was sustained for at least 6 h. However, the dopaminergic cells became refractory to progesterone with continuous treatment for 12 h to 10 days. Progesterone (10–100 nM) treatment suppressed TH activity in a concentration-dependent manner. The inhibitory effect of progesterone was dependent on prior exposure to estradiol. Whereas progesterone decreased TH activity, A ring-reduced metabolites of progesterone did not alter TH activity, suggesting that the response was specific to progesterone. Progesterone decreased radiolabeled phosphate incorporation into TH protein. Okadaic acid, a phosphoprotein phosphatase inhibitor, prevented the progesterone-induced suppression of TH activity and phosphate incorporation into TH, implicating dephosphorylation of TH as the cellular mechanism. In contrast, neither TH mRNA levels nor TH protein content was altered after 1 or 12 h of progesterone treatment. Progesterone decreased TH activity after pretreatment of the hypothalamic cells for 2 or 24 h with actinomycin D, an RNA synthesis inhibitor, suggesting that increased transcription does not mediate the effect. These data indicate that the acute progesterone-induced decline in TH activity is caused by dephosphorylation of TH.

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“…There are a variety of anatomical [4-6, 12, 21, 22], physiological [7], and biochemical [2,8,25] characteristics which seem to refiect sex specificity in the adult. The data in this report indicate we are now able to recognize several biochemical characteristics of the de veloping brain which may permit anticipation of the course of behavioral differentiation.…”

Section: Discussionmentioning

confidence: 99%

Brain Regional Levels of Neurotransmitter Amines as Neurochemical Correlates of Sex-Specific Ontogenesis in the Rat

Wilson¹,

Agrawal²

1979

Dev Neurosci

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Brain regional levels of three neurotransmitter amines – serotonin (5-HT), norepinephrine (NE), dopamine (DA) – were measured in young rats prior to weaning to determine the extent to which modifications in levels of amines might reflect alterations in the sex steroid hormonal environment during the first postnatal week in the life of the rat. Sex-related levels of DA, NE, and 5-HT were found in some brain regions of the 12-day-old rat. Male midbrain DA exceeded the corresponding female value while female hypothalamic NE levels were greater than those of the male. Levels of 5-HT in the corpus striatum and the midbrain of males were greater than those of the female. Castration of the male on day 1 or testosterone propionate (TP) administration to the newborn female resulted in modifications of levels of midbrain 5-HT which reflected feminization of the castrated males and masculinization of the TP-treated females. Castration on day 1, or diethylstilbestrol given on days 2, 4, and 6, resulted in apparent feminization of NE levels in the hypothalamus of 12-day-old male rats. Thus, it appears that regional levels of hypothalamic NE and midbrain 5-HT in the 12-day-old rat may reflect the course of brain organizational activity which becomes recognizable in the adult as sex-specific behavior.

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Influence of Ovariectomy and Ovarian Steroids on Hypothalamic Tyrosine Hydroxylase Activity in the Rat13

Cited by 106 publications

References 16 publications

A Confocal Microscopic Study of Gonadotropin-Releasing Hormone (GnRH) Neuron Inputs to Dopaminergic Neurons Containing Estrogen Receptor α in the Arcuate Nucleus of GnRH-Green Fluorescent Protein Transgenic Mice

A Confocal Microscopic Study of Gonadotropin-Releasing Hormone (GnRH) Neuron Inputs to Dopaminergic Neurons Containing Estrogen Receptor α in the Arcuate Nucleus of GnRH-Green Fluorescent Protein Transgenic Mice

Progesterone Induces Dephosphorylation and Inactivation of Tyrosine Hydroxylase in Rat Hypothalamic Dopaminergic Neurons

Brain Regional Levels of Neurotransmitter Amines as Neurochemical Correlates of Sex-Specific Ontogenesis in the Rat

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