Endocrinology

2019 ◽  
Author(s):  
Stevan R. Emmett ◽  
Nicola Hill ◽  
Federico Dajas-Bailador
Keyword(s):  
Pituitary Gland ◽  
Anterior Pituitary ◽  
Third Ventricle ◽  
Sella Turcica ◽  
Blood Stream ◽  
Neurosecretory Cells ◽  
Thyroid Stimulating Hormone ◽  
Pituitary Stalk ◽  
Portal System ◽  
Pituitary Cells

The pituitary gland (hypophysis) is an endocrine organ located at the base of the skull in a bony recess, called the sella turcica, consisting primarily of an anterior (adenohypophysis) and posterior (neurohypophysis) lobe. Collectively, under the influence of the hypothalamus, these lobes control the hormone secretions responsible for growth, reproduction, behaviour/ emotion, metabolism, and homeostasis, via a complex interplay of feedback loops. Dysfunction through failed synthesis of hormones, ‘breaks’ in the feedback pathways, or receptor malfunction can have diverse effects on plasma hormone levels and, hence, end organ function. The hypothalamus is located within the base of the third ventricle in the diencephalon and is responsible for maintaining homeostasis, as well as influencing emo­tion and behaviour. It is linked to the pituitary gland, which sits outside the dura, via the pituitary stalk and the hypothalamic– hypophyseal portal system. The anterior pituitary lobe makes up about 80% of the pituitary gland and is linked indirectly to the hypothalamus. It receives hormones released from neurosecretory cells in the paraventricular region of the hypothalamus, via a dense network of capillaries that make up the hypothalamic– hypophyseal portal system. These hormones subsequently bind to specific receptors on the pituitary cells to regulate a number of physio­logical processes including stress, growth, metabolism, reproduction, and lactation. There are six hormones re­leased by the anterior pituitary— adrenocorticotropic hormone (ACTH), growth hormone (GH), thyroid-stimulating hormone (TSH), follicle- stimulating hor­mone (FSH)/ luteinizing hormone (LH), and prolactin (PRH) (see Table 4.1). The posterior pituitary lobe is controlled via axons and nerve terminals that extend down from the hypothalamus through the pituitary stalk and into the lobe, which sub­sequently releases neurohormones (oxytocin and vaso­pressin) into the blood stream (see Table 4.2). Vasopressin (also called antidiuretic hormone, ADH), is essential in maintaining fluid homeostasis to ensure adequate blood volume and salt concentration. Its release is modulated by osmoreceptors (rising osmolality) in the hypothal­amus and baroreceptors (falling BP) in the cardiovascular system, and acts directly on the distal nephron to ensure water is conserved. Dysregulation of ADH may lead to conditions such as diabetes insipidus (DI) or SIADH (syn­drome of inappropriate ADH).

Pituitary tumours

2019 ◽  
pp. 299-320
Author(s):  
Kanna Gnanalingham ◽  
Zsolt Zador ◽  
Tara Kearney ◽  
Federico Roncaroli ◽  
H. Rao Gattamaneni
Keyword(s):  
Pituitary Gland ◽  
Anterior Pituitary ◽  
Horizontal Plane ◽  
Third Ventricle ◽  
Sella Turcica ◽  
Thyroid Stimulating Hormone ◽  
Posterior Lobe ◽  
Recommended Treatment ◽  
Stimulating Hormone

The pituitary gland occupies the sella turcica, approximately 5 cm posterior to the tip of the nose in the midline of the skull base. It is closely related to the hypothalamus and third ventricle superiorly, chiasm and lamina terminalis anterosuperiorly, sphenoid sinus anteroinferiorly, cavernous sinus and cavernous segment of the carotid artery laterally, the posterior clinoids and clivus posteriorly. There are two distinct components to the pituitary gland, the anterior and posterior lobe, which are derived from the ectoderm and neuroectoderm, respectively. The anterior pituitary constitutes 80% of the gland mass and in the horizontal plane it is distributed into two lateral wings. The hormones produced by the anterior pituitary are adrenocorticotropic hormone, prolactin, growth hormone, thyroid-stimulating hormone, follicle-stimulating hormone, and luteinizing hormone. This chapter looks in detail at the role of the pituitary gland, what happens when it becomes tumorous, and the recommended treatment avenues.

The Endocrine System: Pituitary Gland

2017 ◽  
Author(s):  
Omer Doron ◽  
Jose E Cohen ◽  
Iddo Paldor
Keyword(s):  
Pituitary Gland ◽  
Human Body ◽  
Sella Turcica ◽  
Endocrine System ◽  
Portal System ◽  
Balance Growth ◽  
Sexual Drive ◽  
Pituitary Dysfunction ◽  
Physiologic Function ◽  
And Function

The pituitary gland is the main point where the neural and endocrine systems function in continuity, maintaining homeostasis of many functional elements of the human body. Located inside the sella turcica, it is separated from the rest of the central nervous system (CNS); however, it plays a crucial part in the regulation of the fundamental endocrine profile, inhibiting or promoting CNS signaling to the rest of the human body. Made up of two distinct tissue subtypes, this gland is fed by a complex vascular network, which enables communication beyond the blood-brain barrier. Lying in close proximity to both important neural and vascular structure, changes in gland size and function result in significant clinical impact. The pituitary gland controls many processes, among which are thermoregulation; metabolism and metabolic rate; glucose, solute, and water balance; growth and development; blood pressure; and sexual drive, pregnancy, childbearing, birth, and breast-feeding. The devastating effects of pituitary dysfunction underscore the importance of the pituitary gland in maintenance of the various functions that underlie normal everyday human activity. This review covers the basic aspects of pituitary gland development, anatomy, and physiologic function. This review contains 3 figures, and 38 references, Key words: adenohypophysis, neurohypophysis, pituitary-hypothalamic axis, pituitary portal system, sella turcica

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.

The Endocrine System: Pituitary Gland

2017 ◽  
Author(s):  
Omer Doron ◽  
Jose E Cohen ◽  
Iddo Paldor
Keyword(s):  
Pituitary Gland ◽  
Human Body ◽  
Sella Turcica ◽  
Endocrine System ◽  
Portal System ◽  
Balance Growth ◽  
Sexual Drive ◽  
Pituitary Dysfunction ◽  
Physiologic Function ◽  
And Function

The pituitary gland is the main point where the neural and endocrine systems function in continuity, maintaining homeostasis of many functional elements of the human body. Located inside the sella turcica, it is separated from the rest of the central nervous system (CNS); however, it plays a crucial part in the regulation of the fundamental endocrine profile, inhibiting or promoting CNS signaling to the rest of the human body. Made up of two distinct tissue subtypes, this gland is fed by a complex vascular network, which enables communication beyond the blood-brain barrier. Lying in close proximity to both important neural and vascular structure, changes in gland size and function result in significant clinical impact. The pituitary gland controls many processes, among which are thermoregulation; metabolism and metabolic rate; glucose, solute, and water balance; growth and development; blood pressure; and sexual drive, pregnancy, childbearing, birth, and breast-feeding. The devastating effects of pituitary dysfunction underscore the importance of the pituitary gland in maintenance of the various functions that underlie normal everyday human activity. This review covers the basic aspects of pituitary gland development, anatomy, and physiologic function. This review contains 3 figures, and 38 references, Key words: adenohypophysis, neurohypophysis, pituitary-hypothalamic axis, pituitary portal system, sella turcica

Posttraumatic Anterior Hypopituitarism—Revisited: The Role of TRH Provocative Release of Prolactin in the Confirmation of Anterior Pituitary Damage

PEDIATRICS ◽  
1977 ◽  
Vol 59 (6) ◽  
pp. 948-950
Author(s):  
David R. Brown ◽  
J. Michael McMillin
Keyword(s):  
Pituitary Gland ◽  
Anterior Pituitary ◽  
Thyroid Stimulating Hormone ◽  
Anterior Pituitary Gland ◽  
Serum Prolactin ◽  
Pituitary Insufficiency ◽  
Closed Head Trauma ◽  
One Year ◽  
Stimulating Hormone

We have previously reported a case of anterior pituitary insufficiency in a 14-year-old girl following closed head trauma.1 Endocrine evaluation one year after her accident revealed hypopituitarism manifested by cachexia, hypothyroidism, hypogonadism, and hypoadrenocorticism. Laboratory studies demonstrated deficiencies of adrenocorticotropic hormone, thyroid-stimulating hormone (TSH), growth hormone, and gonadotropic hormones (follicle-stimulating hormone and luteinizing hormone). We postulated that her hypopituitarism was due to anterior pituitary gland destruction rather than stalk section or hypothalamic damage. We have recently measured her serum prolactin concentrations following provocative stimulation with thyrotropin-releasing hormone (TRH), and these results strengthen the evidence for direct anterior pituitary gland destruction and provide a more complete delineation of her endocrinologic function.

Effects of photoperiod on lactotrophs and on dopaminergic and 5-hydroxytryptaminergic neurones in bull calves

1991 ◽  
Vol 129 (1) ◽  
pp. 141-148 ◽  
Author(s):  
S. A. Zinn ◽  
L. T. Chapin ◽  
K. J. Lookingland ◽  
K. E. Moore ◽  
H. A. Tucker
Keyword(s):  
Pituitary Gland ◽  
Anterior Pituitary ◽  
Plaque Assay ◽  
Brain Regions ◽  
Anterior Pituitary Gland ◽  
Pituitary Stalk ◽  
Serum Concentrations ◽  
Secretory Rate ◽  
Gland Weight ◽  
Bull Calves

ABSTRACT This study was conducted to determine whether photoperiod-induced changes in serum concentrations of prolactin in cattle were associated with changes in activity of dopamine or 5-hydroxytryptamine (5-HT) neurones in the infundibulum/pituitary stalk and the secretion rate and number of lactotrophs in the anterior pituitary gland. Sixteen prepubertal bull calves (approximately 8 weeks of age) were divided into two groups. One group of eight was maintained on a photoperiod of 8 h light : 16 h darkness (8L : 16D) and the other group was exposed to 16L : 8D for 4 weeks. At this time calves were injected with a decarboxylase inhibitor (m-hydroxybenzylhydrazine dihydrochloride, NSD 1015) which blocks the conversion of dihydroxyphenylalanine (DOPA) to dopamine and of 5-hydroxytryptophan (5-HTP) to 5-HT. Calves were killed with pentobarbital 15 min later. Accumulations of DOPA and 5-HTP in selected brain regions were used as indices of activity of dopamine and 5-HT neurones respectively. Secretory rate and number of prolactinsecreting lactotrophs were determined by reverse haemolytic plaque assay. Relative to calves exposed to 8L : 16D, exposure to 16L : 8D increased serum concentrations of prolactin by eightfold, anterior pituitary gland weight by 23%, release of prolactin from pituitary explants by 57% and the area of the plaque for prolactin-secreting lactotrophs by 70%. There was no difference in the rates of accumulation of DOPA and 5-HTP in the infundibulum/pituitary stalk of animals exposed to 4 weeks of 16L : 8D or 8L : 16D. It was concluded that increased serum concentrations of prolactin in bulls exposed to a photoperiod of 16L : 8D for 4 weeks were associated with increased secretion of prolactin from lactotrophs which was not the result of a coincident reduction in activity of dopamine neurones or an activation of 5-HT neurones that terminate in the infundibulum/pituitary stalk. Journal of Endocrinology (1991) 129, 141–148

scholarly journals Reporter Expression, Induced by a Growth Hormone Promoter-Driven Cre Recombinase (rGHp-Cre) Transgene, Questions the Developmental Relationship between Somatotropes and Lactotropes in the Adult Mouse Pituitary Gland

Endocrinology ◽  
2007 ◽  
Vol 148 (5) ◽  
pp. 1946-1953 ◽  
Author(s):  
Raul M. Luque ◽  
Geraldine Amargo ◽  
Shinya Ishii ◽  
Corrinne Lobe ◽  
Roberta Franks ◽  
...  
Keyword(s):  
Pituitary Gland ◽  
Transgenic Mouse ◽  
Anterior Pituitary ◽  
Adult Mouse ◽  
Small Subset ◽  
Parental Line ◽  
Pituitary Cells ◽  
Placental Alkaline Phosphatase ◽  
Developmental Studies ◽  
Mouse Pituitary

This report describes the development and validation of the rGHp-Cre transgenic mouse that allows for selective Cre-mediated recombination of loxP-modified alleles in the GH-producing cells of the anterior pituitary. Initial screening of the rGHp-Cre parental line showed Cre mRNA was specifically expressed in the anterior pituitary gland of adult Cre+/− mice and cephalic extracts of e17 Cre+/− fetuses. Heterozygote rGHp-Cre transgenic mice were crossbred with Z/AP reporter mice to generate Cre+/−,Z/AP+/− offspring. In this model system, the GH promoter-driven, Cre-mediated recombination of the Z/AP reporter leads to human placental alkaline phosphatase (hPLAP) expression that serves to mark cells that currently produce GH, in addition to cells that would have differentiated from GH cells but currently do not express the GH gene. Double immunocytochemistry of adult male and female Cre+/−,Z/AP+/− pituitary cells revealed the majority (∼99%) of GH-producing cells of the anterior pituitary also expressed hPLAP, whereas ACTH-, TSH-, and LH-producing cells were negative for hPLAP, confirming previous reports that corticotropes, thyrotropes, and gonadotropes develop independently of the somatotrope lineage. A small subset (∼10%) of the prolactin-producing cells was positive for hPLAP, consistent with previous reports showing lactotropes can arise from somatotropes during pituitary development. However, the fact that 90% of prolactin-producing cells were negative for hPLAP suggests that the majority of lactotropes in the adult mouse pituitary gland develop independently of the somatotrope lineage. In addition to developmental studies, the rGHp-Cre transgenic mouse will provide a versatile tool to study the role of a variety of genes in somatotrope function and neoplastic transformation.

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.

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