scholarly journals Expression and regulation of glucocorticoid-induced leucine zipper in the developing anterior pituitary gland

2008 ◽  
Vol 42 (2) ◽  
pp. 171-183 ◽  
Author(s):  
Laura E Ellestad ◽  
Stefanie A Malkiewicz ◽  
H David Guthrie ◽  
Glenn R Welch ◽  
Tom E Porter
Keyword(s):  
Pituitary Gland ◽  
Anterior Pituitary ◽  
Leucine Zipper ◽  
Pituitary Hormones ◽  
Neuroendocrine System ◽  
Pituitary Hormone ◽  
Pituitary Cells ◽  
Mrna Levels ◽  
Anterior Pituitary Hormone

The expression profile of glucocorticoid-induced leucine zipper (GILZ) in the anterior pituitary during the second half of embryonic development in the chick is consistent with in vivo regulation by circulating corticosteroids. However, nothing else has been reported about the presence of GILZ in the neuroendocrine system. We sought to characterize expression and regulation of GILZ in the chicken embryonic pituitary gland and determine the effect of GILZ overexpression on anterior pituitary hormone levels. Pituitary GILZ mRNA levels increased during embryogenesis to a maximum on the day of hatch, and decreased through the first week after hatch. GILZ expression was rapidly upregulated by corticosterone in embryonic pituitary cells. To determine whether GILZ regulates hormone gene expression in the developing anterior pituitary, we overexpressed GILZ in embryonic pituitary cells and measured mRNA for the major pituitary hormones. Exogenous GILZ increased prolactin mRNA above basal levels, but not as high as that in corticosterone-treated cells, indicating that GILZ may play a small role in lactotroph differentiation. The largest effect we observed was a twofold increase in FSH β subunit in cells transfected with GILZ but not treated with corticosterone, suggesting that GILZ may positively regulate gonadotroph development in a manner not involving glucocorticoids. In conclusion, this is the first report to characterize avian GILZ and examine its regulation in the developing neuroendocrine system. We have shown that GILZ is upregulated by glucocorticoids in the embryonic pituitary gland and may regulate expression of several pituitary hormones.

Vasopressin as a neuroendocrine regulator of anterior pituitary hormone secretion

1993 ◽  
Vol 129 (6) ◽  
pp. 489-496 ◽  
Author(s):  
Andreas Kjær
Keyword(s):  
Arginine Vasopressin ◽  
Mode Of Action ◽  
Anterior Pituitary ◽  
Hormone Secretion ◽  
Pituitary Hormones ◽  
Pituitary Hormone ◽  
Anterior Pituitary Hormones ◽  
Anterior Pituitary Hormone

Secretion of the anterior pituitary hormones adrenocorticotropin (ACTH), β-endorphin and prolactin (PRL) is complex and involves a variety of factors. This review focuses on the involvement of arginine-vasopressin (AVP) in neuroendocrine regulation of these anterior pituitary hormones with special reference to receptor involvement, mode of action and origin of AVP. Arginine-vasopressin may act via at least two types of receptors: V1− and V2−receptors, where the pituitary V1−receptor is designated V1b. The mode of action of AVP may be mediating, i.e. anterior pituitary hormone secretion is transmitted via release of AVP, or the mode of action may be permissive, i.e. the presence of AVP at a low and constant level is required for anterior pituitary hormones to be stimulated. Under in vivo conditions, the AVP-induced release of ACTH and β-endorphin is mainly mediated via activation of hypothalamic V1− receptors, which subsequently leads to the release of corticotropin-releasing hormone. Under in vitro conditions, the AVP-stimulated release of ACTH and β-endorphin is mediated via pituitary V1b− receptors. The mode of action of AVP in the ACTH and β-endorphin response to stress and to histamine, which is involved in stress-induced secretion of anterior pituitary hormones, is mediating (utilizing V1− receptors) as well as permissive (utilizing mainly V1− but also V2−receptors). The AVP-induced release of PRL under in vivo conditions is conveyed mainly via activation of V1−receptors but V2−receptors and probably additional receptor(s) may also play a role. In stress- and histamine induced PRL secretion the role of AVP is both mediating (utilizing V1 −receptors) and permissive (utilizing both V1− and V2− receptors). Arginine-vasopressin may be a candidate for the PRL-releasing factor recently identified in the posterior pituitary gland. Arginine-vasopressin of both magno- and parvocellular origin may be involved in the regulation of anterior pituitary hormone secretion and may reach the corticotrophs and the lactotrophs via three main routes: the peripheral circulation, the long pituitary portal vessels or the short pituitary portal vessels.

scholarly journals IGF-I regulates pro-opiomelanocortin and GH gene expression in the mouse pituitary gland

2003 ◽  
Vol 178 (1) ◽  
pp. 71-82 ◽  
Author(s):  
J Honda ◽  
Y Manabe ◽  
R Matsumura ◽  
S Takeuchi ◽  
S Takahashi
Keyword(s):  
Pituitary Gland ◽  
Anterior Pituitary ◽  
Northern Blotting ◽  
Pituitary Cells ◽  
Mrna Levels ◽  
Gh Treatment ◽  
Gh Receptor ◽  
Pomc Mrna ◽  
Igf I ◽  
Mouse Pituitary

IGF-I is expressed in somatotrophs, and IGF-I receptors are expressed in most somatotrophs and some corticotrophs in the mouse pituitary gland. Our recent study demonstrated that IGF-I stimulates the proliferation of corticotrophs in the mouse pituitary. These results suggested that somatotrophs regulate corticotrophic functions as well as somatotrophic functions by the mediation of IGF-I molecules. The present study aimed to clarify factors regulating pituitary IGF-I expression and also the roles exerted by IGF-I within the mouse anterior pituitary gland. Mouse anterior pituitary cells were isolated and cultured under serum-free conditions. GH (0.5 or 1 microg/ml), ACTH (10(-8) or 10(-7) M), GH-releasing hormone (GHRH; 10(-8) or 10(-7) M), dexamethasone (DEX; 10(-8) or 10(-7) M) and estradiol-17beta (e2; 10(-11) or 10(-9) M) were given for 24 h. IGF-I mRNA levels were measured using competitive RT-PCR, and GH and pro-opiomelanocortin (POMC) mRNA levels were measured using Northern blotting analysis. GH treatment significantly increased IGF-I mRNA levels (1.5- or 2.1-fold). ACTH treatment did not alter GH and IGF-I mRNA levels. IGF-I treatment decreased GH mRNA levels (0.7- or 0.5-fold), but increased POMC mRNA levels (1.8-fold). GH treatment (4 or 8 microg/ml) for 4 days increased POMC mRNA levels. GHRH treatment increased GH mRNA levels (1.3-fold), but not IGF-I mRNA levels. DEX treatment significantly decreased IGF-I mRNA levels (0.8-fold). e2 treatment did not affect IGF-I mRNA levels. GH receptor mRNA, probably with GH-binding protein mRNA, was detected in somatotrophs, and some mammotrophs and gonadotrophs by in situ hybridization using GH receptor cDNA as a probe. These results suggested that IGF-I expression in somatotrophs is regulated by pituitary GH, and that IGF-I suppresses GH expression and stimulates POMC expression at the transcription level. Pituitary IGF-I produced in somatotrophs is probably involved in the regulation of somatotroph and corticotroph functions.

scholarly journals In Vivo and In Vitro Arsenic Exposition Induces Oxidative Stress in Anterior Pituitary Gland

2016 ◽  
Vol 35 (4) ◽  
pp. 463-475 ◽  
Author(s):  
Sonia A. Ronchetti ◽  
María S. Bianchi ◽  
Beatriz H. Duvilanski ◽  
Jimena P. Cabilla
Keyword(s):  
Oxidative Stress ◽  
Pituitary Gland ◽  
Anterior Pituitary ◽  
Inorganic Arsenic ◽  
Anterior Pituitary Gland ◽  
Pituitary Cells ◽  
Prolactin Release ◽  
Stress Responsive Genes

Inorganic arsenic (iAs) is at the top of toxic metalloids. Inorganic arsenic-contaminated water consumption is one of the greatest environmental health threats worldwide. Human iAs exposure has been associated with cancers of several organs, neurological disorders, and reproductive problems. Nevertheless, there are no reports describing how iAs affects the anterior pituitary gland. The aim of this study was to investigate the mechanisms involved in iAs-mediated anterior pituitary toxicity both in vivo and in vitro. We showed that iAs administration (from 5 to 100 ppm) to male rats through drinking water increased messenger RNA expression of several oxidative stress-responsive genes in the anterior pituitary gland. Serum prolactin levels diminished, whereas luteinizing hormone (LH) levels were only affected at the higher dose tested. In anterior pituitary cells in culture, 25 µmol/L iAs significantly decreased prolactin release in a time-dependent fashion, whereas LH levels remained unaltered. Cell viability was significantly reduced mainly by apoptosis evidenced by morphological and phosphatidylserine externalization studies. This process is characterized by early depolarization of mitochondrial membrane potential and increased levels of reactive oxygen species. Expression of some key oxidative stress-responsive genes, such as heme oxygenase-1 and metallothionein-1, was also stimulated by iAs exposure. The antioxidant N-acetyl cysteine prevented iAs-induced effects on the expression of oxidative stress markers, prolactin release, and apoptosis. In summary, the present work demonstrates for the first time that iAs reduces prolactin release both in vivo and in vitro and induces apoptosis in anterior pituitary cells, possibly resulting from imbalanced cellular redox status.

scholarly journals Neuroendocrine Plasticity in the Anterior Pituitary: Gonadotropin-Releasing Hormone-Mediated Movement in Vitro and in Vivo

Endocrinology ◽  
2007 ◽  
Vol 148 (4) ◽  
pp. 1736-1744 ◽  
Author(s):  
Amy M. Navratil ◽  
J. Gabriel Knoll ◽  
Jennifer D. Whitesell ◽  
Stuart A. Tobet ◽  
Colin M. Clay
Keyword(s):  
Pituitary Gland ◽  
Anterior Pituitary ◽  
Fluorescent Protein ◽  
Cell Movement ◽  
Pituitary Cells ◽  
Rous Sarcoma ◽  
Cytoskeleton Disruption ◽  
Green Fluorescent

The secretion of LH is cued by the hypothalamic neuropeptide, GnRH. After delivery to the anterior pituitary gland via the hypothalamic-pituitary portal vasculature, GnRH binds to specific high-affinity receptors on the surface of gonadotrope cells and stimulates synthesis and secretion of the gonadotropins, FSH, and LH. In the current study, GnRH caused acute and dramatic changes in cellular morphology in the gonadotrope-derived αT3-1 cell line, which appeared to be mediated by engagement of the actin cytoskeleton; disruption of actin with jasplakinolide abrogated cell movement and GnRH-induced activation of ERK. In live murine pituitary slices infected with an adenovirus-containing Rous sarcoma virus-green fluorescent protein, selected cells responded to GnRH by altering their cellular movements characterized by both formation and extension of cell processes and, surprisingly, spatial repositioning. Consistent with the latter observation, GnRH stimulation increased the migration of dissociated pituitary cells in transwell chambers. Our data using live pituitary slices are a striking example of neuropeptide-evoked movements of cells outside the central nervous system and in a mature peripheral endocrine organ. These findings call for a fundamental change in the current dogma of simple passive diffusion of LH from gonadotropes to capillaries in the pituitary gland.

Comparison of anterior pituitary hormone levels in the inferior petrosal sinuses and peripheral blood in various pituitary disorders during perihypophysial phlebography

1991 ◽  
Vol 124 (3) ◽  
pp. 258-266 ◽  
Author(s):  
Gaetano Lombardi ◽  
Bartolomeo Merola ◽  
Annamaria Colao ◽  
Paolo Miletto ◽  
Giovanni De Chiara ◽  
...  
Keyword(s):  
Peripheral Blood ◽  
Anterior Pituitary ◽  
Pituitary Hormones ◽  
Pituitary Hormone ◽  
Inferior Petrosal Sinus ◽  
Hormone Levels ◽  
Anterior Pituitary Hormone ◽  
Two Factors ◽  
The Right ◽  
Concentration Ratios

Abstract. The present study aimed at evaluating the anterior pituitary hormone levels in the inferior petrosal sinuses and in the peripheral blood of 55 patients affected by various pituitary disorders and undergoing perihypophysial phlebography on neurosurgical indication or for diagnostic purposes. The results indicated that in 6 patients with Cushing's disease and in 4 with hyperprolactinemia the secreting adenoma could be localized by inferior petrosal sinus sampling. Furthermore, the concentrations of all the pituitary hormones were found to be higher in the right and/or in the left inferior petrosal sinus than in peripheral blood, showing a clear gradient between central and peripheral samples. Moreover, the evaluation of hormone central/peripheral concentration ratios revealed noteworthy differences, namely, that central/peripheral concentration ratios of GH, ACTH, and PRL were significantly higher than those of TSH, FSH, and LH (p<0.01). On the contrary, no significant differences were found when the concentration ratios of GH, ACTH and PRL or TSH, FSH and LH were compared among themselves. This finding may be attributed to at least two factors: the increased pulsatility and the relatively short biological halftime of polypeptic hormones (GH, ACTH, and PRL) compared with glycoprotein hormones (TSH, FSH, and LH).

Toward Multifactorial Hypothalamic Regulation of Anterior Pituitary Hormone Secretion

Physiology ◽  
1999 ◽  
Vol 14 (2) ◽  
pp. 54-58
Author(s):  
W. R. Crowley
Keyword(s):  
Neuropeptide Y ◽  
Anterior Pituitary ◽  
Hormone Secretion ◽  
Pituitary Hormones ◽  
Gonadotropin Releasing Hormone ◽  
Pituitary Hormone ◽  
Anterior Pituitary Hormone ◽  
Hypothalamic Hormones ◽  
Hypothalamic Regulation ◽  
Hypophysial Portal

The hypothalamus regulates the secretion of anterior pituitary hormones via release of releasing hormones into the hypophysial portal vasculature. Additional neuromessengers act at the pituitary to modulate responses to the hypothalamic hormones. For example, neuropeptide Y enhances the effect of gonadotropin-releasing hormone and the response to the prolactin-inhibiting hormone dopamine.

3. The mysteries of reproduction

2014 ◽  
pp. 34-47
Author(s):  
Martin Luck
Keyword(s):  
Reproductive Cycle ◽  
Anterior Pituitary ◽  
Pituitary Hormones ◽  
Chorionic Gonadotrophin ◽  
Gender Development ◽  
Pituitary Hormone ◽  
General Effect ◽  
Anterior Pituitary Hormone ◽  
Human Menopausal Gonadotrophin ◽  
And Gender

‘The mysteries of reproduction’ begins with Pergonal (human menopausal gonadotrophin), a hormone preparation extracted from urine which contains pituitary hormones crucial to the reproductive cycle. Prolactin, another anterior pituitary hormone, affects fertility in women, but is also found in many different kinds of animal and has more than 300 different actions. Prolactin has the general effect of controlling the movement of salts and water across membranes, especially in tissues related to the skin. The important roles of hormones—progesterone, chorionic gonadotrophin, prostaglandin, oxytocin, oestrogen, and testosterone—in the reproductive cycle, human and gender development, the menopause, and the ageing process are also described.

scholarly journals Rat Anterior Pituitary Folliculostellate Cells Are Targets of Interleukin-1β and a Major Source of Intrapituitary Follistatin

Endocrinology ◽  
2003 ◽  
Vol 144 (2) ◽  
pp. 732-740 ◽  
Author(s):  
Louise M. Bilezikjian ◽  
Angela M. O. Leal ◽  
Amy L. Blount ◽  
Anne Z. Corrigan ◽  
Andrew V. Turnbull ◽  
...  
Keyword(s):  
Anterior Pituitary ◽  
Cell Function ◽  
Pituitary Hormones ◽  
Pituitary Cells ◽  
Mrna Levels ◽  
Mrna Accumulation ◽  
Folliculostellate Cells ◽  
Pituitary Adenylate Cyclase ◽  
Immortalized Cell ◽  
Insight Into

Folliculostellate cells of the anterior pituitary are postulated to be an important source of factors, such as follistatin, that regulate pituitary function by intercellular communication. To gain further insight into the function of this cell type, folliculostellate cells were enriched from cultured rat anterior pituitary cells, and an immortalized cell line designated FS/D1h was established and characterized. These FS/D1h cells express S100 immunoreactivity and produce IL-6 but not pituitary hormones such as GH, ACTH, FSH, and LH. Importantly, FS/D1h cells express large amounts of follistatin mRNA and secrete the protein, as quantified indirectly by the amount of [125I]activin A immunoprecipitated with a follistatin antiserum. The FS/D1h cells also express α, βA, and βB inhibin/activin subunit mRNAs, but whether they produce the corresponding activins and inhibins has not been determined. The response of FS/D1h cells to agents thought to modulate folliculostellate cell function was evaluated. IL-1β (0.005–5 nm) stimulated the secretion of follistatin and increased mRNA expression. In parallel, IL-6 secretion was stimulated. Dexamethasone, pituitary adenylate cyclase-activating polypeptide(1–27), and lipopolysaccharide but not testosterone, 12-O-tetradecanoylphorbol-13-acetate, or forskolin also increased follistatin secretion. Surprisingly, activin had no effect on follistatin mRNA levels, despite the fact that FS/D1h cells express ActRII, ActRIIB, and ALK-4 (ActRIB). Activin, on the other hand, induced Smad7 mRNA accumulation and exerted an antiproliferative effect on FS/D1h cells. Altogether, these observations support the possibility that follistatin originating from folliculostellate cells participates in mediating the effects of IL-1β, glucocorticoids, and other agents on the response of pituitary cells to activins.

scholarly journals In vivo xenoestrogenic actions of cadmium and arsenic in anterior pituitary and uterus

Reproduction ◽  
2016 ◽  
Vol 152 (1) ◽  
pp. 1-10 ◽  
Author(s):  
Sonia A Ronchetti ◽  
Gisela V Novack ◽  
María S Bianchi ◽  
Melisa C Crocco ◽  
Beatriz H Duvilanski ◽  
...  
Keyword(s):  
Pituitary Gland ◽  
Anterior Pituitary ◽  
Hormone Secretion ◽  
Anterior Pituitary Gland ◽  
Ovariectomized Rats ◽  
Serum Prolactin ◽  
Pituitary Hormone ◽  
Low Doses ◽  
Proliferation Markers

Cadmium (Cd) and arsenic (iAs) are toxic metals ubiquitously present in the environment. Both pollutants exert nonmonotonic dose responses, being mostly cytotoxic at high concentrations but mimicking estrogen (E2) effects at low doses. Xenoestrogenic activity of Cd and iAs has been demonstrated in different hormone-dependent tumor cell lines; however, their actionsin vivoremain largely unknown. Here, we investigated whetherin vivoadministration of low doses of Cd and iAs through drinking water would display xenoestrogenic effects in the anterior pituitary gland and uterus of ovariectomized rats. Cd (1ppm) and iAs (0.1ppm) exposure increased the wet weight of anterior pituitary gland and uterus and induced proestrus- and estrus-like vaginal smears. Both metals stimulate cell proliferation of these tissues as they increased the expression of proliferation markers. More importantly, they augmented soluble guanylyl cyclase α1 subunit expression, which has been linked to hormone-dependent tumor progression. Also, Cd and iAs modified protein levels of full-length estrogen receptor α and its truncated variants in an E2-like manner. Anterior pituitary hormone secretion was differentially affected by both metals. Luteinizing hormone synthesis and release were strongly diminished after Cd exposure and only mildly reduced by iAs. Both metals were able to increase prolactin synthesis, although only iAs augmented serum prolactin levels. This study shows for the first time that Cd and iAs exert strong xenoestrogenic effects on anterior pituitary gland at low doses. The differences between Cd and iAs E2-like behavior indicate that other Cd- and iAs-specific mechanisms could be involved. Altogether, these results contribute to the knowledge of reproductive disorders associated with Cd and iAs environmental contamination.

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