Immunocytochemical Localization of Estrogen Receptor in Various Anterior Pituitary Hormone Cells of Adult Male and Female Rats.

Kikuta, Toshiteru; Yamamoto, Kazutoshi; Namiki, Hideo; Hayashi, Shinji

doi:10.1267/ahc.26.609

Cited by 14 publications

(10 citation statements)

References 32 publications

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“…The estrous cycle produces dynamic changes in the gonadotrope and lactotrope cells which undergo a series of maturational stages culminating in secretion in proes trus [40.41], Recently, Kikuta et al [12] observed that the high ER level at proestrus was due to an increase in the ER content of gonadotropes and lactotropes, in agree ment with previous data of Muldoon and Singh [38], The lactotrope-specific expression of the ER variant on proes trus day may suggest some physiological function for this isoform. However, an effect of this variant is dependent on the translation into protein.…”

Section: Discussionmentioning

confidence: 99%

“…Spain, 1994. transcription factors. Works over the past decade using ligand-binding assays, autoradiography, and more recent ly immunocytochemistry demonstrated that ER is con centrated in gonadotropes, somatotropes, and lactotropes [9][10][11][12], However, precise mechanisms through which Ei exerts its action on pituitary cell specific functions have not been fully established. The increase in progesterone receptor (PR), a typical E?…”

Section: Introductionmentioning

confidence: 99%

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Sex- and Cell-Specific Expression of an Estrogen Receptor Isoform in the Pituitary Gland

Demay¹,

Tiffoche²,

Thieulant³

1996

Neuroendocrinology

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The presence of multiple monomeric forms has been described for the estrogen receptor (ER) in the pituitary gland. We analyzed ER mRNA forms in male and female rat pituitary. A single 6.2-kb ER mRNA species was detected in the male rat pituitary, whereas the female rat pituitary exhibited two ER mRNA forms of 6.2 and 5.5 kb, respectively. The 6.2-kb mRNA was present throughout the different stages of the estrous cycle, while the 5.5-kb mRNA appeared to be restricted to proestrus, suggesting an acute regulation of ER transcription at this stage. The 5.5-kb ER mRNA could be rapidly induced either by 17β-estradiol replacement in ovariectomized adult female rats or by priming immature rats with pregnant-mare serum gonadotropin. Using enriched cell populations, an inverse and strong correlation was established between the presence of the 5.5-kb ER mRNA form and the number of gonadotropes. Conversely, the localization of the 5.5-kb mRNA form was demonstrated in lactotrope populations. In order to elucidate the structural modifications in the transiently expressed ER mRNA, a series of reverse-transcriptase polymerase chain reaction amplifications was carried out using several pairs of primers corresponding to the entire ER-coding region. The data showed that no alternative splicing was occurring in the ER-coding region involving a potential role of either 3’- or 5’-untranslated regions. Thus, ER presents a 17β-estradiol-dependent transcriptional mechanism triggered on proestrous day and specific to the female lactotropes.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Sex- and Cell-Specific Expression of an Estrogen Receptor Isoform in the Pituitary Gland

Demay¹,

Tiffoche²,

Thieulant³

1996

Neuroendocrinology

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“…In designing these experiments, however, additional times were tested as potential points at which gonadotropes may be activated. For example, gonadotropes translate gonadotropin mRNA (Childs et al 1992a(Childs et al ,b,1994a, and produce receptors for estradiol (Kikuta et al 1993) and GnRH (Lloyd and Childs 1988) during diestrus. Peak transcriptional activity for gonadotropin ␤-subunit mRNA occurs during the LH surge late in proestrus (for LH ␤ mRNA) or during the FSH rise in early estrus (for FSH ␤ mRNA) (reviewed in Childs et al 1994a).…”

Section: Figurementioning

confidence: 99%

“…Therefore, the factors that regulate this early expression are not known. Perhaps the fos expression by metestrous or estrous LH gonadotropes reflects its involvement in the synthesis of LH ␤ proteins (Childs et al 1994a), and/or estradiol (Kikuta et al 1993) or GnRH receptors (Childs et al 1994b;Lloyd and Childs 1988). …”

Section: Figurementioning

confidence: 99%

Differential Expression of c-fos In Vitro by All Anterior Pituitary Cell Types During the Estrous Cycle: Enhanced Expression by Luteinizing Hormone but Not by Follicle-stimulating Hormone Cells

Armstrong

Childs

1997

J Histochem Cytochem.

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C-fos expression appears in some activated cell types. Because of dynamic changes in gonadotropes during the estrous cycle, this study was initiated to determine if fos might be expressed in gonadotropes before any period of activation. We detected c-fos and pituitary antigens in dissociated anterior pituitary cells by dual-labeling immunocytochemistry. The highest percentage of cells with fos protein were found in proestrous rat populations. In diestrous and proestrous populations, dual labeling showed that 6-9% of pituitary cells contained fos with adrenocorticotropin, thyroid-stimulating hormone, prolactin, or growth hormone antigens. In contrast, only 0.8-3% contained fos with luteinizing hormone (LH) or follicle-stimulating hormone (FSH) antigens. We then tested the hypothesis that gonadotropes might increase fos expression earlier in the cycle. In populations from metestrous rats, c-fos labeling was found in 45% of LH cells compared to only 23% of LH cells in the proestrous group. This suggests that proportionately more LH cells are being activated to produce fos early in the cycle. Perhaps fos is used in translation of LH beta antigens or gonadotropin-releasing hormone (GnRH) receptor mRNAs. In contrast, less than 1% of all pituitary cells expressed fos with FSH at all stages of the cycle (only 6-12% of FSH cells). This differential expression suggests one mechanism behind the regulation of non-parallel storage and release of gonadotropin antigens.

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“…During the past decade, however, this proof has not been forthcoming for two reasons. First, there has been controversy about the presence or types of estrogen receptors on somatotropes (Kikuta et al, 1993;Friend et al, 1994;Shupnik, 2002;Stefanneau et al, 1994;Zafer et al, 1995;Chaidarun et al, 1997;Chaidarun et al,m 1998;Gittoes et al, 1999;Shupnik et al1998;Hal and McDonnell, 1999). Second, not all in vitro studies have demonstrated an estrogen-mediated increase in GH synthesis or secretion (Webb et al, 1983;Simard et al, 1985;Lam et al, 1996;Tulipano et al, 2004;Fukuta and Martin, 1986;Silverman et al, 1988;Hauspie et al, 2003.).…”

mentioning

confidence: 99%

Estrogen mediated cross talk between the ovary and pituitary somatotrope

Childs

Iruthayanathan

Akhter

et al. 2006

Molecular and Cellular Endocrinology

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Immunocytochemical Localization of Estrogen Receptor in Various Anterior Pituitary Hormone Cells of Adult Male and Female Rats.

Cited by 14 publications

References 32 publications

Sex- and Cell-Specific Expression of an Estrogen Receptor Isoform in the Pituitary Gland

Sex- and Cell-Specific Expression of an Estrogen Receptor Isoform in the Pituitary Gland

Differential Expression of c-fos In Vitro by All Anterior Pituitary Cell Types During the Estrous Cycle: Enhanced Expression by Luteinizing Hormone but Not by Follicle-stimulating Hormone Cells

Estrogen mediated cross talk between the ovary and pituitary somatotrope

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