Galanin gene expression in radiothyroidectomy-induced thyrotroph adenomas

1996 ◽  
Vol 271 (1) ◽  
pp. E24-E30
Author(s):  
J. F. Hyde ◽  
J. P. Moore ◽  
K. W. Drake ◽  
D. G. Morrison
Keyword(s):  
Gene Expression ◽  
Thyroid Hormones ◽  
Anterior Pituitary ◽  
Human Growth ◽  
Mrna Levels ◽  
Male Mice ◽  
Pituitary Glands ◽  
Positive Regulators ◽  
Hypothalamic Pituitary Axis ◽  
Iodine 131

Galanin gene expression is markedly increased in the anterior pituitary glands of estrogen-treated rats (lactotroph hyperplasia) as well as human growth hormone-releasing hormone transgenic mice (somatotroph hyperplasia). The objective of this study was to examine galanin in a mouse model of thyrotroph adenoma formation. Male mice were radiothyroidectomized by use of iodine-131 (131I), and galanin peptide levels were assessed in the hypothalamic-pituitary axis. Immunoreactive galanin concentrations in the anterior pituitaries of 131I-treated mice were decreased 80% at 3, 6, 9, and 12 mo after radiothyroidectomy. Galanin peptide levels in the hypothalamus were decreased 20-25% at these times. Treatment with either estradiol or 3,3',5-triiodo-L-thyronine increased galanin peptide concentrations in the anterior pituitaries of 131I-treated mice, but neither treatment restored galanin concentrations. Galanin mRNA levels were decreased > 80% 1 yr after radiothyroidectomy. We conclude that, unlike animal models of lactotroph and somatotroph hyperplasia, galanin gene expression is suppressed throughout the development of thyrotroph adenomas, suggesting that galanin does not have a stimulatory role in the proliferation of thyrotrophs. Moreover, these data show that thyroid hormones are important positive regulators of galanin gene expression in the mouse and that estrogen may stimulate galanin gene expression in the absence of thyroid hormones.

scholarly journals Ontogeny of pituitary thyrotrophs and regulation by endogenous thyroid hormone feedback in the chick embryo

2005 ◽  
Vol 184 (2) ◽  
pp. 407-416 ◽  
Author(s):  
Michael Muchow ◽  
Ioannis Bossis ◽  
Tom E Porter
Keyword(s):  
Thyroid Hormone ◽  
Thyroid Hormones ◽  
Anterior Pituitary ◽  
Feedback Regulation ◽  
Thyroid Stimulating Hormone ◽  
Mrna Levels ◽  
Hormone Production ◽  
Negative Feedback Regulation ◽  
Cephalic Lobe ◽  
Whole Mount

Increased thyroid hormone production is essential for hatching of the chick and for the increased metabolism necessary for posthatch endothermic life. However, little is known about the ontogeny and distribution of pituitary thyrotrophs during this period or whether pituitary thyroid-stimulating hormone (TSH) production is regulated by endogenous thyroid hormones during chick embryonic development. This study assessed the abundance and location of pituitary thyrotrophs and the regulation of TSHβ peptide and mRNA levels by endogenous thyroid hormones prior to hatching. TSHβ-containing cells were first detected on embryonic day (e) 11, and the thyrotroph population increased to maximum levels on e17 and e19 and then decreased prior to hatching (d1). Thyrotroph distribution within the cephalic lobe of the anterior pituitary was determined on e19 by whole-mount immunocytochemistry for TSHβ peptide and by whole-mount in situ hybridization for TSHβ mRNA. Thyrotroph distribution within the cephalic lobe was heterogeneous among embryos, but most commonly extended from the ventral medial region to the dorsal lateral regions, along the boundary of the cephalic and caudal lobes. Inhibition of endogenous thyroid hormone production with methi-mazole (MMI) decreased plasma thyroxine (T4) levels and increased pituitary TSHβ mRNA levels on e19 and d1. However, control pituitaries contained significantly more TSHβ peptide than MMI-treated pituitaries on e17 and e19, suggesting higher TSH secretion into the blood in MMI-treated groups. We conclude that thyrotroph abundance and TSH production increase prior to hatching, that thyrotrophs are localized heterogenenously within the cephalic lobe of the anterior pituitary at that time, and that TSH gene expression and secretion are under negative feedback regulation from thyroid hormones during this critical period of development.

Evidence of thyrotropin-releasing hormone (TRH) gene expression in rat anterior pituitaries and modulation by estrogens of TRH-like immunoreactivity and TRH-elongated peptide contents

1996 ◽  
Vol 151 (1) ◽  
pp. 87-96 ◽  
Author(s):  
G Croissandeau ◽  
N Schussler ◽  
D Grouselle ◽  
P Pagesy ◽  
C Rauch ◽  
...  
Keyword(s):  
Gene Expression ◽  
Thyroid Hormones ◽  
Anterior Pituitary ◽  
Cross Reactivity ◽  
Plasma Prolactin ◽  
Ovx Rats ◽  
First Time ◽  
Intact Rats

Abstract TRH gene expression in the anterior pituitary has previously been reported in the human in vivo and in the rat in vitro. Until now, modulation of this synthesis with glucocorticoids and thyroid hormones has been observed in rats. The present study demonstrates for the first time that the TRH gene is also expressed, in vivo, in the rat anterior pituitary and that anterior pituitary TRH-like immunoreactivity (TRH-LI) and elongated forms of the immediate TRH progenitor sequence (TRH-elongated peptide) contents are also modulated by estrogens (E2). To investigate the presence of proTRH mRNA in the rat anterior pituitary, total RNA was reverse transcribed (RT) and the RT products were then amplified by PCR. Treatments with E2 were performed on intact and ovariectomized (OVX) rats for 2 months. TRH-LI was measured by RIA with an antibody which did not recognize the TRH-like peptide, pGlu-Glu-Pro-NH2 (<EEP-NH2) (cross-reactivity <0·1%) and was characterized further as TRH-LI by HPLC. TRH-elongated peptides were measured by EIA and characterized by Sephadex G-50 chromatography and immunoblotting (molecular mass 25–35 kDa). The plasma prolactin levels and the pituitary sizes were increased by E2 treatment in both intact and OVX rats. Anterior pituitary TRH-LI increased in intact E2-treated rats compared with intact rats (82·7 ± 19·0 versus 39·6 ± 3·6 fmol/mg protein; means ± s.e.m.; P<0·001). This increase was greater when E2 was administered to OVX rats (599·0 ± 98·4 after E2 treatment versus 58·6 ± 3·6 fmol/mg protein; P<0·001). In intact rats, anterior pituitary TRH-elongated peptide contents were not modified by E2 treatment while they were significantly decreased in OVX E2-treated rats (144·6 ±8·8 versus 223·7 ± 9·5 fmol/mg protein; P<0·001). These results demonstrate TRH gene expression in the rat anterior pituitary in vivo and suggest that E2 treatment is responsible for an increase in anterior pituitary TRH-LI, together with a decrease in TRH-elongated peptide contents. Journal of Endocrinology (1996) 151, 87–96

scholarly journals Gene Expression Profiling in Liver of Mice Fed a High-Fat Diet Supplemented With Watermelon Flesh, Arginine, or Citrulline Shows Similar Pattern Changes

2021 ◽  
Vol 5 (Supplement_2) ◽  
pp. 303-303
Author(s):  
Mikayla Chen ◽  
Neil Shay
Keyword(s):  
Gene Expression ◽  
High Fat Diet ◽  
Expression Patterns ◽  
Cytochrome P450 Monooxygenases ◽  
Mrna Levels ◽  
Male Mice ◽  
High Fat ◽  
Total Rna ◽  
P450 Monooxygenases ◽  
Close Relationship

Abstract Objectives Watermelon is a nutrient-dense fruit known to contain high levels or arginine and citrulline; these two compounds may influence the nitric oxide pathway, vasodilation, and thus be hypotensive. We tested the hypothesis that when C57BL/6J male mice fed a high-fat diet (HF) had additions to the HF diet of either watermelon flesh (WF), arginine (ARG) or citrulline (CIT), changes in gene expression patterns would occur vs. those seen in HF. Further, we hypothesize that patterns of expression seen in WF, ARG, and CIT groups would be somewhat similar based on increased dietary levels of ARG and CIT in all three groups. Methods Following prior work (Becraft et al.; 2018, Egea et al. 2020), groups of mice were provided either a low-fat diet (LF, 10% kcal fat), high-fat diet (HF, 45% kcal fat), HF plus Watermelon Flesh (WF), HF plus 1% (w/w) arginine (ARG) or 1% (w/w citrulline (CIT) for 10 weeks. Watermelon flesh was provided at 10% of total energy. After ten weeks, animals were euthanized, and liver total RNA was isolated using Trizol. Total RNA was then used for gene expression analysis (N = 4 per group) using Clariom S microarrays and TAC analysis software (ThermoFisher). Results Mice fed WF, ARG, and CIT had several shared canonical pathways of gene expression, including eicosanoid metabolism via cytochrome P450 monooxygenases and exercise-induced circadian rhythm (All P &lt; 0.05). Intake of WF and ARG significantly up-regulated both Cyp2c9 and Cyp2c38 mRNA levels (P &lt; 0.05). The Bst2 gene was significantly down-regulated in all three groups compared to HF mice (P &lt; 0.05). The Cyp2b9 gene was upregulated ∼10.7 fold in WF, and &gt; 1000-fold in ARG mice (P &lt; 0.05). Conclusions We demonstrated that when added to a HF diet, WF, ARG, and CIT all produced a change in hepatic gene expression in male mice. Possibly due to the close relationship of ARG and CIT metabolism, and high content of ARG and CIT in WF, expression patterns observed in all three groups demonstrated a high degree of similarity. Several genes, including Cyp2c9, Cyp2c38, and Elvol5 were up-regulated; these genes may be involved in modifying steroids and arachidonic acid and other long-chain fatty acids. Funding Sources National Watermelon Promotion Board.

scholarly journals Gene expression and secretion of LH and FSH in relation to gene expression of GnRH receptors in the brushtail possum (Trichosurus vulpecula) demonstrates highly conserved mechanisms

Reproduction ◽  
2009 ◽  
Vol 137 (1) ◽  
pp. 129-140 ◽  
Author(s):  
J L Crawford ◽  
D A Heath ◽  
L J Haydon ◽  
B P Thomson ◽  
D C Eckery
Keyword(s):  
Gene Expression ◽  
Mrna Expression ◽  
Oestrous Cycle ◽  
Brushtail Possum ◽  
Mrna Levels ◽  
Gonadotrophin Secretion ◽  
Pituitary Glands ◽  
Sampling Regime ◽  
And Storage

In eutherian mammals, the gonadotrophins (LH and FSH) are synthesized and stored in gonadotroph cells under the regulation of multiple mechanisms including GnRH. Very little is known about the regulation of gonadotrophin secretion and storage in pituitary glands of marsupials. This study revealed, using quantitative PCR and heterologous RIA techniques, thatLHBmRNA expression levels remained constant over the oestrous cycle, regardless of the presence of a preovulatory LH surge, which is characteristic of a hormone secreted under regulation. Our sampling regime was unable to detect pulses of LH during the follicular phase, althoughGNRHRmRNA levels had increased at this time. Pulses of LH were, however, detected in the luteal phase of cycling females, in anoestrus females and in males. There was a positive correlation between gene expression ofFSHBand plasma levels of FSH at different stages of the oestrous cycle and no pulses of FSH were detected at any time; all characteristics of a hormone secreted via the constitutive pathway. Usingin situhybridisation and immunohistochemistry methods, we determined that mRNA expression ofLHBandFSHB, and protein storage of gonadotrophins exhibited a similar pattern of localisation within the pituitary gland. Additionally, sexual dimorphism of gonadotroph populations was evident. In summary, these findings are similar to that reported in eutherians and considering that marsupial evolution diverged from eutherians over 100 million years ago suggests that the regulation of gonadotrophins is highly conserved indeed.

The effect of thyroid hormones on growth hormone gene expression in vivo in rats

1987 ◽  
Vol 112 (3) ◽  
pp. 459-463 ◽  
Author(s):  
D. F. Wood ◽  
J. A. Franklyn ◽  
K. Docherty ◽  
D. B. Ramsden ◽  
M. C. Sheppard
Keyword(s):  
Gene Expression ◽  
Thyroid Hormones ◽  
Time Course ◽  
Hormone Replacement ◽  
Detailed Examination ◽  
Growth Hormone Gene ◽  
Mrna Levels ◽  
Thyroid Hormone Replacement ◽  
Serum Gh

ABSTRACT Thyroid hormones are important regulators of GH synthesis and secretion. In this study we have made a detailed examination of the time-course of the effects of hypothyroidism and tri-iodothyronine (T3) replacement in the intact rat on GH gene expression in the anterior pituitary gland. Changes in pituitary cytoplasmic GH messenger (m)RNA levels were compared with total pituitary GH content and serum GH concentration during the development of hypothyroidism and following short-term T3 replacement in vivo. Hypothyroidism was associated with a fall in pituitary GH mRNA levels. Treatment of hypothyroid animals with T3 rapidly stimulated GH mRNA levels to values above those seen in euthyroid controls. The reduction in GH mRNA levels seen during the development of hypothyroidism was accompanied by a fall in serum GH and pituitary GH content, both of which were partially restored by T3 replacement. Thus thyroid hormone replacement in hypothyroidism rapidly stimulates GH mRNA synthesis, which is followed by the gradual restoration of pituitary GH stores and serum GH concentration. J. Endocr. (1987) 112, 459–463

scholarly journals Changes in Gene Expression during Pituitary Morphogenesis and Organogenesis in the Chick Embryo

Endocrinology ◽  
2011 ◽  
Vol 152 (3) ◽  
pp. 989-1000 ◽  
Author(s):  
Monika Proszkowiec-Weglarz ◽  
Stacy E. Higgins ◽  
Tom E. Porter
Keyword(s):  
Gene Expression ◽  
Mrna Expression ◽  
Anterior Pituitary ◽  
Molecular Mechanisms ◽  
Expression Profiles ◽  
Expression Patterns ◽  
Mrna Levels ◽  
Pituitary Development ◽  
Excellent Model ◽  
Functional Development

The anterior pituitary gland plays an important role in the regulation of many physiological processes. Formation of Rathke's pouch (RP), the precursor of the anterior pituitary, involves evagination of the oral ectoderm in a multi-step process regulated by cell interactions, signaling pathways, and transcription factors. Chickens are an excellent model to study development because of the availability of large sample sizes, accurate timing of development, and embryo accessibility. The aim of this study was to quantify mRNA expression patterns in the developing chicken anterior pituitary to evaluate the chicken embryo as a model for mammalian pituitary development. The expression profiles of 16 genes differentially expressed in RP and neuroectoderm were determined in this study. Among these, Pitx1, Pitx2, and Hesx1 mRNA levels were high on embryonic days (e) 2.5 to e3 in RP and decreased during development. Expression of Pit1 and Tbx19 mRNA in RP reached the highest levels by e7 and e6.5, respectively. Levels of glycoprotein subunit α mRNA increased beginning at e4. FGF8 mRNA showed the highest expression at e3 to e3.5 in neuroectoderm. BMP2 showed slight decreases in mRNA expression in both tissues during development, while Isl1 and Noggin mRNA expression increased in later development. Taken together, we present the first quantitative transcriptional profile of pituitary organogenesis. Our results will help further understanding of the functional development of this gland. Moreover, because of the high similarity in gene expression patterns observed between chicken and mouse, chickens could serve as an excellent model to study genetic and molecular mechanisms underlying pituitary development.

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