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The Veterinary Clinics of North... Dec 1987The clinical signs and endocrinologic abnormalities that characterize horses with pituitary, thyroid, and adrenal dysfunction are described. Laboratory tests and... (Review)
Review
The clinical signs and endocrinologic abnormalities that characterize horses with pituitary, thyroid, and adrenal dysfunction are described. Laboratory tests and hormonal assays useful for evaluating horses with suspected endocrinopathies are discussed.
Topics: Adrenal Glands; Animals; Endocrine System Diseases; Horse Diseases; Horses; Pituitary Gland; Thyroid Gland
PubMed: 3322531
DOI: 10.1016/s0749-0739(17)30669-7 -
Pituitary Feb 2015Recent studies suggest that adult pituitary stem cells may play a role in pituitary tumorigenesis. We sought to explore whether the Glial cell-line derived neurotrophic...
PURPOSE
Recent studies suggest that adult pituitary stem cells may play a role in pituitary tumorigenesis. We sought to explore whether the Glial cell-line derived neurotrophic factor receptor alpha 2 (GFRα2), a recently described pituitary stem/progenitor marker, might be differentially expressed in pituitary adenomas versus normal pituitary.
METHODS
The expression of GFRα2 and other members of the GFR receptor family (GFRα1, α3, α4) were analyzed using RT-PCR, western blot, and immunohistochemistry in 39 pituitary adenomas, 14 normal pituitary glands obtained at autopsy, and cDNA from 3 normal pituitaries obtained commercially.
RESULTS
GFRα2 mRNA was ~2.6 fold under-expressed in functioning adenomas (p < 0.01) and ~3.5 fold over-expressed in non-functioning adenomas (NFAs) (p < 0.05) compared to normal pituitary. Among NFAs, GFRα2 was significantly over-expressed (~5-fold) in the gonadotropinoma subtype only (p < 0.05). GFRα2 protein expression appeared to be higher in most NFAs, although there was heterogeneity in protein expression in this group. GFRα2 protein expression appeared consistently lower in functioning adenomas by IHC and western blot. In normal pituitary, GFRα2 was localized in Rathke's remnant, the putative pituitary stem cell niche, and in corticotropes.
CONCLUSION
Our results suggest that the pituitary stem cell marker GFRα2 is under-expressed in functioning adenomas and over-expressed in NFAs, specifically gonadotropinomas. Further studies are required to elucidate whether over-expression of GFRα2 in gonadotropinomas might play a role in pituitary tumorigenesis.
Topics: Adenoma; Adult; Aged; Female; Gene Expression Regulation, Neoplastic; Glial Cell Line-Derived Neurotrophic Factor; Humans; Immunohistochemistry; Male; Middle Aged; Pituitary Gland; Pituitary Neoplasms; Reverse Transcriptase Polymerase Chain Reaction; Young Adult
PubMed: 24402129
DOI: 10.1007/s11102-014-0553-1 -
AJNR. American Journal of Neuroradiology Feb 2012Patients with transfusional iron overload develop iron deposits in the pituitary gland, which are associated with volume loss and HH. The purpose of this study was to...
BACKGROUND AND PURPOSE
Patients with transfusional iron overload develop iron deposits in the pituitary gland, which are associated with volume loss and HH. The purpose of this study was to characterize R2 and volumetric data in a healthy population for diagnostic use in patients with transfusional iron overload.
MATERIALS AND METHODS
One hundred healthy controls without iron overload between the ages of 2 and 48 were recruited to have MR imaging of the brain to assess their pituitary R2 and volume. Pituitary R2 was assessed with a 8-echo spin-echo sequence, and pituitary volumes, by a 3D spoiled gradient-echo sequence with 1-mm(3) resolution. A 2-component continuous piecewise linear approximation was used for creating volumetric and R2 nomograms. Equations were generated from regression relationships for convenient z-score calculation.
RESULTS
Pituitary R2 rose weakly with age (r(2) = 0.19, P < .0001). Anterior and total pituitary volumes increased steadily up to 18 years of age, after which volume slightly decreased. Females had larger pituitary glands, most likely representing their larger lactotroph population.
CONCLUSIONS
From these data, a clinician can calculate the z scores for R2 and pituitary volume in patients with iron overload. Normal ranges are well-differentiated from values previously associated with endocrine disease in transfusional siderosis; this finding suggests that preclinical iron overload can be recognized and appropriately treated.
Topics: Adolescent; Adult; Child; Child, Preschool; Female; Humans; Iron; Magnetic Resonance Imaging; Male; Middle Aged; Organ Size; Pituitary Gland; Reference Values; Young Adult
PubMed: 22081683
DOI: 10.3174/ajnr.A2788 -
Frontiers in Neuroendocrinology Apr 2007Interoceptive feedback signals from the body are transmitted to hypothalamic neurons that control pituitary hormone release. This review article describes the... (Review)
Review
Interoceptive feedback signals from the body are transmitted to hypothalamic neurons that control pituitary hormone release. This review article describes the organization of central neural pathways that convey ascending visceral sensory signals to endocrine neurons in the paraventricular (PVN) and supraoptic nuclei (SON) of the hypothalamus in rats. A special emphasis is placed on viscerosensory inputs to corticotropin releasing factor (CRF)-containing PVN neurons that drive the hypothalamic-pituitary-adrenal axis, and on inputs to magnocellular PVN and SON neurons that release vasopressin (AVP) or oxytocin (OT) from the posterior pituitary. The postnatal development of these ascending pathways also is considered.
Topics: Animals; Hypothalamus; Neurons; Neurons, Afferent; Neuropeptides; Pituitary Gland; Viscera
PubMed: 17391741
DOI: 10.1016/j.yfrne.2007.02.002 -
Neuroendocrinology 2015The recent demonstration using genetic tracing that in the adult pituitary stem cells are normally recruited from the niche in the marginal zone and differentiate into... (Review)
Review
The recent demonstration using genetic tracing that in the adult pituitary stem cells are normally recruited from the niche in the marginal zone and differentiate into secretory cells in the adenopituitary has elegantly confirmed the proposal made when the pituitary stem cell niche was first discovered 5 years ago. Some of the early controversies have also been resolved. However, many questions remain, such as which are the markers that make a pituitary stem cell truly unique and the exact mechanisms that trigger recruitment from the niche. Little is known about the processes of commitment and differentiation once a stem cell has left the niche. Moreover, the acceptance that pituitary cells are renewed by stem cells implies the existence of regulated mechanisms of cell death in differentiated cells which must themselves be explained. The demonstration of an apoptotic pathway mediated by RET/caspase 3/Pit-1/Arf/p53 in normal somatotrophs is therefore an important step towards understanding how pituitary cell number is regulated. Further work will elucidate how the rates of the three processes of cell renewal, differentiation and apoptosis are balanced in tissue homeostasis after birth, but altered in pituitary hyperplasia in response to physiological stimuli such as puberty and lactation. Thus, we can aim to understand the mechanisms underlying human disease due to insufficient (hypopituitarism) or excess (pituitary tumor) cell numbers.
Topics: Adult Stem Cells; Animals; Apoptosis; Cell Differentiation; Humans; Models, Animal; Pituitary Gland; Stem Cell Niche
PubMed: 25662152
DOI: 10.1159/000375502 -
The American Journal of Pathology Oct 2001The myosin superfamily of molecular motor proteins includes conventional myosins and several classes of unconventional myosins. Recent studies have characterized the...
The myosin superfamily of molecular motor proteins includes conventional myosins and several classes of unconventional myosins. Recent studies have characterized the human and mouse unconventional myosin XVA, which has a role in the formation and/or maintenance of the unique actin-rich structures of inner ear sensory hair cells. Myosin XVA is also highly expressed in human anterior pituitary cells. In this study we examined the distribution of myosin XVA protein and mRNA in normal and neoplastic human pituitaries and other neuroendocrine cells and tumors. Myosin XVA was expressed in all types of normal anterior pituitary cells and pituitary tumors and in other neuroendocrine cells and tumors including those of the adrenal medulla, parathyroid, and pancreatic islets. Most nonneuroendocrine tissues examined including liver cells were negative for myosin XVA protein and mRNA, although the distal and proximal tubules of normal kidneys showed moderate immunoreactivity for myosin XVA. Ultrastructural immunohistochemistry localized myosin XVA in association with secretory granules of human anterior pituitary cells and human pituitary tumors. These data suggest that in neuroendocrine cells myosin XVA may have a role in secretory granule movement and/or secretion.
Topics: Endocrine Gland Neoplasms; Humans; Immunohistochemistry; In Situ Hybridization; Microscopy, Electron; Molecular Sequence Data; Myosins; Nervous System Neoplasms; Neurosecretory Systems; Pituitary Gland
PubMed: 11583965
DOI: 10.1016/S0002-9440(10)62524-2 -
Neuroendocrinology 2017Kisspeptins are important regulators of the development and function of the hypothalamic-pituitary-gonadal axis. However, the importance of kisspeptin at the pituitary...
BACKGROUND
Kisspeptins are important regulators of the development and function of the hypothalamic-pituitary-gonadal axis. However, the importance of kisspeptin at the pituitary level is unclear.
METHODS
We examined the expression profile of kisspeptin in the mouse pituitary during development and in adulthood using RT-PCR, quantitative PCR and immunohistochemistry.
RESULTS
Kiss1 mRNA was detected in both embryonic and postnatal pituitaries. Kisspeptin-immunoreactive (+) cells were detected from embryonic day (E) 13.5 throughout adulthood, being localized to the rostroventral portion in the anterior pituitary (AP) in embryos, and also to the dorsocaudal AP postnatally. A large proportion of kisspeptin+ cells were double-labeled with gonadotrope markers including Foxl2, SF-1, and LHβ, and the percentage of LHβ+ cells in kisspeptin+ cells increased during development. No kisspeptin+ cells were positive for the proliferating cell marker MCM7 (minichromosome maintenance protein 7), but a few kisspeptin+ cells co-expressed the stem/progenitor cell marker Sox2. Kisspeptin expression was similar between sexes and between agonadal SF-1 knockout embryos and wild-type littermates. Kiss1 mRNA levels were not significantly different between sexes or during early postnatal development, but levels in females increased when puberty began and were significantly higher than in males at postpubertal ages.
CONCLUSIONS
These results suggest that kisspeptin is expressed in gonadotrope precursors during gonadotrope differentiation, and that kisspeptin expression begins soon after the initiation of αGSU production and is extinguished soon after the initiation of LH production. Furthermore, pituitary kisspeptin expression may be regulated in a gonad-independent manner during development, but may be associated with gonadotrope function in adulthood.
Topics: Age Factors; Animals; Animals, Newborn; Embryo, Mammalian; Female; Gene Expression Regulation, Developmental; Gonadotrophs; Hypothalamus; Kisspeptins; Male; Mice; Mice, Inbred C57BL; Mice, Transgenic; Mutation; Pituitary Gland; RNA, Messenger; Steroidogenic Factor 1; Thyrotropin, beta Subunit
PubMed: 27871073
DOI: 10.1159/000453398 -
Journal of Evolutionary Biology Nov 2015At the proximate level, hormones are known to play a critical role in influencing the life history of mammals, including humans. The pituitary gland is directly...
At the proximate level, hormones are known to play a critical role in influencing the life history of mammals, including humans. The pituitary gland is directly responsible for producing several hormones, including those related to growth and reproduction. Although we have a basic understanding of how hormones affect life history characteristics, we still have little knowledge of this relationship in an evolutionary context. We used data from 129 mammal species representing 14 orders to investigate the relationship between pituitary gland size and life history variation. Because pituitary gland size should be related to hormone production and action, we predicted that species with relatively large pituitaries should be associated with fast life histories, especially increased foetal and post-natal growth rates. Phylogenetic analyses revealed that total pituitary size and the size of the anterior lobe of the pituitary significantly predicted a life history axis that was correlated with several traits including body mass, and foetal and post-natal growth rates. Additional models directly examining the association between relative pituitary size and growth rates produced concordant results. We also found that relative pituitary size variation across mammals was best explained by an Ornstein-Uhlenbeck model of evolution, suggesting an important role of stabilizing selection. Our results support the idea that the size of the pituitary is linked to life history variation through evolutionary time. This pattern is likely due to mediating hormone levels but additional work is needed. We suggest that future investigations incorporating endocrine gland size may be critical for understanding life history evolution.
Topics: Animals; Biological Evolution; Body Weight; Mammals; Organ Size; Pituitary Gland; Species Specificity
PubMed: 26249034
DOI: 10.1111/jeb.12715 -
The Journal of Reproduction and... 2014The pituitary is an important endocrine tissue of the vertebrate that produces and secretes many hormones. Accumulating data suggest that several types of cells compose...
The pituitary is an important endocrine tissue of the vertebrate that produces and secretes many hormones. Accumulating data suggest that several types of cells compose the pituitary, and there is growing interest in elucidating the origin of these cell types and their roles in pituitary organogenesis. Therein, the histogenous cell line is an extremely valuable experimental tool for investigating the function of derived tissue. In this study, we compared gene expression profiles by microarray analysis and real-time PCR for murine pituitary tumor-derived non-hormone-producing cell lines TtT/GF, Tpit/F1 and Tpit/E. Several genes are characteristically expressed in each cell line: Abcg2, Nestin, Prrx1, Prrx2, CD34, Eng, Cspg4 (Ng2), S100β and nNos in TtT/GF; Cxcl12, Raldh1, Msx1 and Twist1 in Tpit/F1; and Cxadr, Sox9, Cdh1, EpCAM and Krt8 in Tpit/E. Ultimately, we came to the following conclusions: TtT/GF cells show the most differentiated state, and may have some properties of the pituitary vascular endothelial cell and/or pericyte. Tpit/F1 cells show the epithelial and mesenchymal phenotypes with stemness still in a transiting state. Tpit/E cells have a phenotype of epithelial cells and are the most immature cells in the progression of differentiation or in the initial endothelial-mesenchymal transition (EMT). Thus, these three cell lines must be useful model cell lines for investigating pituitary stem/progenitor cells as well as organogenesis.
Topics: Animals; Biomarkers; Cell Differentiation; Cell Line; Epithelial-Mesenchymal Transition; Gene Expression Profiling; Mice; Pituitary Gland; Transcription Factors
PubMed: 24881870
DOI: 10.1262/jrd.2014-031 -
Journal of Veterinary Internal Medicine 2011Pituitary pars intermedia dysfunction (PPID) is the most common endocrinologic disorder of aged horses.
BACKGROUND
Pituitary pars intermedia dysfunction (PPID) is the most common endocrinologic disorder of aged horses.
HYPOTHESIS/OBJECTIVES
Pituitary glands of PPID-affected horses are larger than those of aged horses without signs of PPID, and the size difference can be detected using computed tomography (CT) imaging.
ANIMALS
Eight horses with clinical signs of PPID and supportive endocrinologic test results and 3 aged control (PPID-negative) horses.
METHODS
Computed tomography examination of the brain and pituitary gland was performed twice in 10 of the 11 horses, approximately 6 months apart. Six PPID-affected horses were treated with pergolide for 6 months between CT scans. The second CT scan was followed by euthanasia and pathologic examination of 6 PPID-affected horses (4 treated horses).
RESULTS
On initial examination, pituitary glands of PPID-affected horses were larger in height (P < .01) and width (P < .01) than controls, but the difference in length was not significant (P = .06). After 6 months of pergolide treatment of PPID-affected horses, pituitary gland length increased (P < .05), but height and width were not different from pretreatment values. There was no difference between pituitary gland measurements made at the terminal CT scans and necropsy. Furthermore, pituitary gland volume calculated from the measurements was highly correlated to pituitary gland weight. Additional CT findings were bilaterally symmetrical mineralization in the thalamus and cholesterol granulomas adjacent to the lateral and fourth ventricles.
CONCLUSIONS AND CLINICAL IMPORTANCE
CT is a useful imaging modality to determine pituitary gland size of PPID-affected horses,and CT measurements are similar to gross pathologic measurements.
Topics: Animals; Brain; Horse Diseases; Horses; Pituitary Diseases; Pituitary Gland; Pituitary Gland, Intermediate; Tomography, X-Ray Computed
PubMed: 21985144
DOI: 10.1111/j.1939-1676.2011.00784.x