In situ hybridization for LHRH mRNA following estrogen treatment

Rothfeld, Joel M.; Hejtmancik, J. F.; Conn, P. Michael; Pfaff, Donald W.

doi:10.1016/0169-328x(89)90045-4

Cited by 60 publications

(25 citation statements)

References 17 publications

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“…It has been reported that estradiol inhibits (31,32), has no effect (33)(34)(35)(36), stimulates (37)(38)(39)(40)(41), or has variable effects (42) on GnRH expression. The variable results in females are most likely due to differences in the experimental paradigms used and to the well characterized positive and negative feedback effects that estradiol has demonstrated to exert on GnRH neurons.…”

Section: Discussionmentioning

confidence: 99%

Cell-specific Expression of the Human Gonadotropin-releasing Hormone Gene in Transgenic Animals

Wolfe

Wray

Westphal

et al. 1996

Journal of Biological Chemistry

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We have previously demonstrated that 1131 base pairs (bp) of the human gonadotropin-releasing hormone (hGnRH) gene promoter can target simian virus 40 T antigen expression to GnRH neurons in transgenic mice. In these animals, GnRH neurons were transformed before they migrated to their final location in the rostral hypothalamus, complicating an analysis of cell-specific expression. To localize regions of the hGnRH promoter that are important for cell-specific expression, we created transgenic mice with various 5-flanking regions of the hGnRH gene fused to the luciferase reporter gene. When 3828 or 1131 bp of the hGnRH promoter 5-flanking DNA were used (؊3828/؉5LUC and ؊1131/؉5LUC, respectively), luciferase expression in adult transgenic mice was observed in the rostral hypothalamus and olfactory tissues, regions which have been shown to be loci of GnRH-expressing neurons. Luciferase expression was not observed in other brain or peripheral tissues. Double-labeled in situ hybridization further demonstrated that luciferase expression was invariably colocalized with GnRH expression. When transgenic animals were created with a construct consisting of 484 bp of the hGnRH 5-flanking DNA fused to the luciferase gene (؊484/؉5LUC), luciferase expression was not observed in the hypothalamus or in olfactory tissues. This is the first report localizing DNA sequences responsible for cell-specific expression of the GnRH gene in vivo.The neurohormone gonadotropin-releasing hormone (GnRH) 1 is a decapeptide that is released from the hypothalamus and regulates the synthesis and release of the pituitary gonadotropins. It has become increasingly clear that the precise coordinated release and expression of GnRH are essential for proper function of the mammalian reproductive system. For example, patients with Kallmann's syndrome do not appear to contain GnRH neurons in the appropriate locations within the hypothalamus due to a failure of the GnRH neurons to migrate from the olfactory placode during development, which manifests as hypogonadotropic hypogonadism (1-3). Until recently, the study of the intracellular mechanisms regulating the release and expression of GnRH has been complicated by both the low numbers of GnRH neurons, as few as 800 in the mouse brain (4), and their scattered distribution from the hypothalamus to the olfactory bulb (5, 44).In humans the GnRH gene consists of four exons and three introns (6 -11), and its expression is limited to a small number of neurons in the brain, to gonadal and mammary tissue (12), and to human placental tissue (10, 13). Interestingly, GnRH expression displays a tissue specificity since the initiation site for placental GnRH expression is different than the initiation site for hypothalamic GnRH expression (10, 13). Recently, transgenic technology has given researchers the tools to study physiological and molecular aspects of the GnRH neuron. By targeting the SV40 T antigen oncogene to mouse GnRH neurons using the rat (GT1 cells (14)) or human (GN11 and NLT cells (15)) GnRH promoter, it h...

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Section: Discussionmentioning

confidence: 99%

Cell-specific Expression of the Human Gonadotropin-releasing Hormone Gene in Transgenic Animals

Wolfe

Wray

Westphal

et al. 1996

Journal of Biological Chemistry

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“…A recent study by Amano et al [65] indicated, by in situ hybridization, an increase in sGnRH mRNA levels in neurons of the preoptic area in juvenile male, but not in female masu salmon, under the effect of 17-a-methyltestosterone. In the rat, both stimula tory [66][67][68][69] and inhibitory [70][71][72] effects of steroids on mRNA levels for mGnRH have been demonstrated. These discrepancies may be correlated with cyclic estro gen changes or with the different protocols used [73].…”

Section: Possible Mechanisms O F Action O F Gonadal Steroids On Gnrh mentioning

confidence: 99%

Differential Regulation of the Two Forms of Gonadotropin-Releasing Hormone (mGnRH and cGnRH-II) by Sex Steroids in the European Female Silver Eel (Anguilla anguilla)

Montero-Hadjadje

et al. 1995

Neuroendocrinology

113

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The effect of steroids on the two gonadotropin-releasing hormone (GnRH) forms present in the eel (mammalian GnRH, mGnRH and chicken GnRH-II, cGnRH-II), as well as on gonadotropin (GTH), was studied using specific radioimmunoassays. Female silver eels received chronic treatments with various steroids (estradiol, testosterone, androstenedione, 5α-androstane-3β,17β-diol). Estradiol or the combination of estradiol and androgens induced increases in brain and pituitary mGnRH levels and pituitary GTH level, whereas androgens given alone had no significant effect. In contrast, androgens or their combination with estradiol reduced brain cGnRH-II levels (this form remaining undetectable in the pituitary), estradiol given alone having no significant effect. This work demonstrates that the two forms of GnRH undergo a differential regulation by steroids, with a positive estrogen-dependent feedback on mGnRH (as well as on GTH) and a negative androgen-dependent feedback on cGnRH-II. These data are in agreement with previous results obtained in experimentally matured female eels (induced by a gonadotropic treatment which stimulates the production of both estrogens and androgens) showing increases in mGnRH and GTH levels, as well as a decrease in cGnRH-II [1]. The positive feedback of steroids on the mGnRH-GTH axis adds credence to the hypothesis according to which mGnRH would be the main form involved in the control of the gonadotropic function. This positive feedback would play an important role, amplifying pubertal stimulation of the gonadotropic axis, in this fish species.

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“…Estradiol has been shown to increase GnRH mRNA in the POA [32, 33, 34]and to decrease it in the OVLT [35, 36]. The presence of an estrogen response element in the GnRH gene and the detection of estrogen receptors in transfected GnRH-expressing cells [37, 38]suggests this gene’s ability to respond to estrogen but whether normal GnRH neurons in vivo contain estrogen receptors remains unclear.…”

Section: Discussionmentioning

confidence: 99%

Differential Gene Expression Response to Gonadal Hormones by Preoptic Regulatory Factors-1 and -2 in the Female Rat Brain

Nowak

Torres

1999

Neuroendocrinology

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Steroids and neuropeptides interact in the central nervous system (CNS) to regulate reproductive function and behavior. The preoptic regulatory factors, PORF-1 and PORF-2, are unique neuropeptides for which roles in gender-related brain development and function have been proposed. PORF-1 and PORF-2 expression in rat brain are age, region and gender dependent, and castration or hypophysectomy alter the metabolism of the PORF-1 and PORF-2 mRNAs in male rat brain and testes. If these two peptides have a role in gender-dependent brain function, then gonadal steroids might well affect their expression. The present study was designed to investigate the response of the PORF-1 and PORF-2 mRNAs to sex steroids in the female rat brain and to compare this response to that of two peptides whose roles in the neuroendocrinology of reproduction are well established, gonadotropin-releasing hormone (GnRH) and neuropeptide Y (NPY). Rats were ovariectomized and treated with placebo, estradiol (E₂), progesterone (P₄) or a combination of the two (E₂/P₄) and NPY, PORF-2, GnRH and PORF-1 mRNAs were quantified by nuclease protection assays. PORF-1, PORF-2 and GnRH mRNAs were also measured in intact rats during estrus and proestrus. Responses were compared in the preoptic anterior hypothalamus (POA), medial basal hypothalamus (MBH), cerebral cortex (CC) and hippocampus (HIPP). Expression of PORF-1 and PORF-2 was also confirmed in the female rat hypothalamus by in situ hybridization analysis. PORF-1 and PORF-2 mRNAs were detected in the adult female rat brain by both in situ hybridization and ribonuclease protection analyses. In situ hybridization analysis demonstrated that PORF-1 and PORF-2 mRNAs are expressed in hypothalamic neurons. RNase protection analysis showed that PORF-1, PORF-2 and NPY mRNAs were present in all four brain regions examined while GnRH expression was detected only in the MBH and POA. Estradiol alone upregulated expression of the PORF-1 and PORF-2 mRNAs in the ovariectomized rat in the POA and HIPP, and of NPY mRNA in the MBH and HIPP. Progesterone alone had a stimulatory effect on NPY mRNA in the MBH and HIPP. Treatment with a combination of E₂/P₄ downregulated PORF-2 mRNA in the POA as well as PORF-1, PORF-2 and NPY mRNAs in the CC. In contrast, E₂/P₄ upregulated the PORF-2 and NPY mRNAs in the HIPP and NPY mRNA in the MBH. In the cycling rat, PORF-1 mRNA levels were higher during proestrus than estrus in both the MBH and POA, while PORF-2 mRNA levels did not change. In contrast GnRH mRNA was lower in the POA and higher in the MBH during proestrus compared with estrus. Thus, intrinsic factors, most likely both ovarian and neuroendocrine, regulate PORF-1 and GnRH expression in the intact cycling rat CNS in a region-dependent manner. In the ovariectomized rat, PORF-1, PORF-2, NPY and GnRH mRNAs all respond in a region-specific manner to sex steroid treatment. These data support the role of PORF-1 and PORF-2 in gender-dependent b...

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In situ hybridization for LHRH mRNA following estrogen treatment

Cited by 60 publications

References 17 publications

Cell-specific Expression of the Human Gonadotropin-releasing Hormone Gene in Transgenic Animals

Cell-specific Expression of the Human Gonadotropin-releasing Hormone Gene in Transgenic Animals

Differential Regulation of the Two Forms of Gonadotropin-Releasing Hormone (mGnRH and cGnRH-II) by Sex Steroids in the European Female Silver Eel (Anguilla anguilla)

Differential Gene Expression Response to Gonadal Hormones by Preoptic Regulatory Factors-1 and -2 in the Female Rat Brain

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