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Query: UNIPROT:P05231 (interleukin-6)
 23,907 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A cell line was obtained from a primary culture of a pleomorphic adenoma of the parotid gland in a 24-year-old woman. The cells of the line (PA 16/23) grew spontaneously in minimal culture conditions and showed stable morphologic characteristics over 30 passages. PA 16/23 cells had immunophenotypic and ultrastructural features similar to those of transformed myoepithelial cells, which are regarded as the precursors of pleomorphic adenomas. Furthermore, these cells have been demonstrated immunocytochemically to contain interleukin-6 (IL-6) on light and electron microscopic examination. IL-6 also has been found by enzyme-linked immunosorbent assay in the culture supernatant and has been proven to be capable of stimulating growth of the PA 16/23 cells.
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PMID:Characterization of a novel cell line from pleomorphic adenoma of the parotid gland with myoepithelial phenotype and producing interleukin-6 as an autocrine growth factor. 132 Apr 46

Preliminary studies have demonstrated that some pituitary adenomas secrete immunoreactive interleukin-6 (irIL-6) when cultured in vitro. We have extended these studies by investigating 100 pituitary adenomas of different types measuring immunoreactive and bioactive IL-6. Tumors were cultured either as explants without fetal calf serum or as dispersed cells with 10% total calf serum. Fifty-three of the 100 (53%) pituitary cultures were found to release irIL-6 and in 44 adenomas examined, 32 (72.7%) secreted bioactive IL-6. In 61 explant cultures, 30 adenomas released IL-6, indicating autonomous secretion. The amount of IL-6 released by adenomas in cell culture was generally higher, although the incidence was similar to explant cultures. IrIL-6 was released by 7 of 14 prolactinomas, 15 of 27 somatotrophinomas, 5 of 7 corticotrophinomas (including 2 Nelson's adenomas), 1 of 1 thyrotrophinomas, 2 of 2 gonadotrophinomas, and 23 of 49 clinically non-functioning adenomas. Periadenomatous tissue removed from a patient with a corticotrophinoma was found to secrete IL-6 but in much lower concentration than from the adenoma tissue. Tumor necrosis factor-alpha and -gamma-interferon were not detected in the conditioned media. Four IL-6-secreting adenomas were examined by in situ hybridization for IL-6 messenger RNA, and three of these were positive with fluorescence present throughout the tissue examined. We have provided evidence that over half of pituitary adenomas secrete IL-6 which is bioactive and that IL-6 is synthesized within the tumor by the adenoma cells.
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PMID:Production of bioactive and immunoreactive interleukin-6 (IL-6) and expression of IL-6 messenger ribonucleic acid by human pituitary adenomas. 828 2

Interleukin-6 (IL-6) was secreted by cultured cells of 7 out of 11 human pituitary adenomas that were examined. Interleukin-1 (IL-1) stimulated IL-6 release after a 24-h incubation period in five of the seven IL-6-secreting adenoma cultures and in all seven after 72 h. Tumour necrosis factor, interferon-gamma and epidermal growth factor did not significantly affect IL-6 secretion. Interleukin-1 failed to induce measurable IL-6 in the cultures that did not secrete IL-6 under basal conditions. Prostaglandin E2 did not influence basal IL-6 secretion and indomethacin did not inhibit IL-1-stimulated IL-6 release. In addition, pertussis toxin had no effect on IL-1-stimulated IL-6 release. The growth hormone (GH) secretory response to IL-1 varied, with stimulation in one GH-secreting adenoma culture, no significant effect in a second and inhibition in a third. Interleukin-1 did not significantly affect the release of prolactin, thyrotrophin, luteinizing hormone or follicle-stimulating hormone in any of the adenoma cultures. This study provides evidence that IL-1 is a stimulator of IL-6 release from cultured human pituitary adenoma cells that secrete IL-6. Stimulation of IL-6 release by IL-1 in these tumour cells is probably not mediated by prostaglandins or by a pertussis toxin-sensitive mechanism.
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PMID:Interleukin-1 stimulates the release of interleukin-6 from cultured human pituitary adenoma cells. 839 Nov 94

Interleukins and their receptors are expressed intrinsically in the anterior pituitary and regulate hormone production and cell proliferation. It has previously been shown that interleukin-6 (IL-6) regulates hormone secretion in normal pituitary cells and cell lines. Here we examined the effects of IL-6 on propiomelanocortin (POMC) expression and ACTH production in corticotroph adenoma cells in vitro. We found that IL-6 stimulates both ACTH secretion and POMC gene expression in corticotroph adenoma cell cultures. This first demonstration of the stimulatory action of IL-6 on human corticotroph adenoma cell function provides further evidence for a direct action of IL-6 on corticotroph pituitary cells. We have confirmed previous reports of IL-6 production by corticotroph adenoma cells and in addition, demonstrated for the first time that the synthetic glucocorticoid dexamethasone is a potent suppressor of intratumoral IL-6 production. This intratumoral produced IL-6 may be in part responsible, in an autocrine manner, for the stimulation of ACTH synthesis and secretion. Our results suggest that IL-6 might play a role in the pathogenesis of Cushing's disease. However, elevated glucocorticoid levels in patients with Cushing's disease may prevent excessive action of IL-6 on ACTH production and tumor progression of corticotroph adenomas in vivo.
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PMID:Interleukin-6 is inhibited by glucocorticoids and stimulates ACTH secretion and POMC expression in human corticotroph pituitary adenomas. 1092 17

In 1994, Zhang et al. of Rockefeller University in New York reported the first successful complementary DNA (cDNA) cloning of leptin by the positional cloning method. Leptin was identified as the gene of ob/ob mouse in genetic obesity syndromes. It has very strong food intake control, and body weight and energy expenditure. The name "leptin" derived from the Greek word leptos, meaning "thin." We hereby review major advances leading to our current finding of leptin, leptin receptor and its structure, the outline of homozygote, and also influence of leptin in the pituitary. (The structure of leptin) The mouse obese gene has been localized to chromosome 6. With human leptin gene on chromosome 7q31.3, its DNA has more than 15000 base pairs and consists of three exons and two introns. For bioactivation of leptin the importance of disulfide-binding site is suggested. Human leptin which replaced the 128-th arginine with glutamine has the function of an aldosteron antagonist, which is reported to have the function of athrocytosis inhibition. The resemblance of leptin precursor of human, mouse and rat is very high, i.e., mouse and rat homology is 96% and mouse and human homology is 83%. (The structure of leptin receptor) The mutant gene, which is the cause of obesity, was shown on map on diabetic mouse (db/db) chromosome 4, and it was proven to be the same as the leptin receptor gene cloned by Tartaglia et all. Further studies have found the Zucker fatty rat (fa/fa) to be incorporated into a linkage map of rat chromosome 5, whose region of rat is the equivalent to the region of conserved synteny of the db/db mouse gene. The leptin receptor is glycoprotein consisting of a single transmembrane-spanning component. The primary structure of leptin receptor belongs to the cytokine-class1 family, the single membrane-spanning receptor, and is highly related to the gp130 signal-transducing component of the interleukin-6 (IL-6) receptor, the granulocyte colony-stimulating factor (G-CSF) receptor, and the leukemia inhibitory factor (LIF) receptor. The leptin receptor is known to have at least six existing isoforms (Ob-Ra, b, c, d, e, f) from the difference in splicing. (Homozygote Mutation of Leptin and Leptin Receptor :Hormone Secretion Disorders) The point mutation of ob/ob mouse and the splicing mutation of db/db mouse show remarkable obesity and hyperphagia. These obesity models show a reproduction disorder with both the male and the female, and they develop with homozygote. The cause is thought to be the gonadotropin secretory abnormality in pituitary. Three family lines report the cases of this deficiency, and it is considered that the secretory abnormality in pituitary develops into hypogonadotropic. These patients show low value in plasma FSHbeta (follicle stimulating hormone-beta and LHbeta (luteinizing hormone-beta which are produced from pituitary, and the plasma GnRH (gonadotropin releasing hormone) level is also low. Furthermore, the leptin receptor deficient family line was reported in 1998, in which case only the homozygote developed. The plasma leptin concentration of normal human is about 8.0 ng/ml, and this case with leptin receptor deficiency has high value of 500-700 ng/ml, which is the equivalent to the db/db mouse. (Role of Leptin in Hypothalamus-Pituitary-Periphery Function) The role of leptin which regulates pituitary hormones suggests the promotion the GHRH (growth hormone releasing hormone) secretion in hypothalamus-pituitary axis, with the possibility of the rise in secretion of GH (growth hormone) in pituitary, i.e. effects of icv (intracerebroventricular) infusion of leptin has spontaneously stimulated GHRH, which promotes GH secretion in the normal rats. On the other hand, topical treatment of GH3 (derived from a rat pituitary GH-secreting cell line) with leptin directly inhibits cell proliferation. The obesity model animals (ob/ob, db/db, fa/fa) have equally plump body compared to the normal models, which shows signs of sufficient growth. (Localization and Functional Relevance of Leptin and Leptin Receptor in Rodents Pituitary) Aside from being the food intake inhibitor and the energy control factor, leptin takes part in controlling the pituitary hormones. Promoting the secretion of GH, PRL (prolactin), TSHbeta (thyroid stimulating hormone-beta, FSHbeta/LHbeta, and inhibiting the secretion of ACTH (adrenocorticotropic hormone) are the major changes of pituitary hormones which are brought on by leptin. The expressive localization is specific, and immunohistochemistry (IHC) method recognized leptin in granular state in FSHbeta, LHbeta and TSHbeta positive cells. In our biochemical examination, the bulk of the expression of leptin is recognized in fraction of the secretory granule. In particular, FSHbeta cells had the highest percentage rate of colocalized leptin in rat pituitary. On the other hand, leptin receptor has been reported to be found only in normal rat pituitary, human pituitary adenoma, and respective cell lines in pituitaries by the RT-PCR method until now, but we disclosed for the first time the localization of leptin receptor on the plasma membrane of GH-secreting cells with the IHC method that has not been cleared so far. These findings show that leptin and leptin receptor have been expressed in different cells, and that the rat pituitary glands entertain paracrine mechanism between leptin (FSHbeta/LHbeta cells) and leptin receptor (GH cells). The function of paracrine in this pituitary suggests a new point of view in hypothalamus-pituitary axis, and it shall be concerned with many aspects such as hormone secretions and proliferation/inhibition. (Human Pituitary Adenoma) Preliminary report of leptin and leptin-receptor relationship with pituitary adenoma that has secretion abnormality has been filed, and its manifestation is being observed by the RT-PCR. Leptin and leptin receptor are expressed in most adenoma, and it is thought to function by autocrine and paracrine pathway in the adenomas. Leptin has been located in ACTH-secreting adenoma most frequently, especially in ACTH carcinoma. The leptin receptor is detected in all adenomas with high percentage rate, with both long and short forms, and then many cases of nonfunctioning pituitary adenomas, compared with other adenomas, have been reported to be positive with both long and short forms of leptin receptor as detected by RT-PCR. The HP75 cell line is derived from the nonfunctioning pituitary adenoma, which produces FSHbeta and LHbeta. The expression of leptin receptor in nonfunctioning pituitary adenoma, and the suppression of HP75 multiplication may lead to the possible hypothesis of leptin becoming one factor for the treatment of pituitary adenoma, especially in gonadotropin adenomas.
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PMID:Leptin and the pituitary. 1182 4

Data on the dural invasiveness of pituitary adenomas have been correlated to the expression of matrix metalloproteinases (e.g. MMP-9). Serine proteases have not yet been investigated in human pituitary adenomas. In this study, paraffin-embedded material from 84 human pituitary adenomas (acromegaly n=18, Cushing's disease n=21, prolactinoma n=18, thyroid-stimulating hormone-secreting adenoma n=1, nonsecreting adenoma n=26) and 9 nontumourous anterior pituitary lobes (obtained from patients with prostate cancer) was immunohistochemically analysed for expression of MMP-2, MMP-9, tissue inhibitor of metalloproteinases-2 (TIMP-2), urokinase-type plasminogen activator (uPA), uPA receptor (uPAR), tissue-type plasminogen activator (tPA), plasminogen activator inhibitor-1 (PAI-1), and interleukin-6 (IL-6). Cavernous sinus invasion was determined by assessment of preoperative magnetic resonance imaging and intraoperative inspection (invasive n=50, noninvasive n=34). In pituitary adenomas, reactions were positive (diffuse expression) to MMP-2 (74% of cases), MMP-9 (49%), TIMP-2 (88%), uPA (89%), uPAR (90%), tPA (69%), and PAI-1 (87%). A weak expression of IL-6 was found in 12% of the adenomas. All reactions were positive (focal expression) in every sample of anterior lobe tissue, except for uPA (negative in 3 out of 9 cases), and IL-6 (faintly positive in 5 out of 8 cases). Adenomas showed remarkably greater expression of uPA than anterior lobe tissue (Chi-square P<0.05). Nonsecreting adenomas exhibited a stronger tendency towards overexpression of uPA in invasive tumours when compared to noninvasive adenomas (Chi-square P=0.053). We found no correlation of MMP-9 expression and tumour invasion. TIMP-2 was overexpressed in noninvasive as compared to invasive adenomas (Chi-square P<0.05). The interrelationship between MMPs and serine proteinases in pituitary adenomas remains to be elucidated. From our data, a correlation between IL-6 and an activation of MMP-9 cannot be proven. The uPA-system may, however, play a role in dural invasion of pituitary adenomas.
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PMID:Expression of serine proteases and metalloproteinases in human pituitary adenomas and anterior pituitary lobe tissue. 1290 90

Estrogens are considered to be critically involved in lactotroph and lactosomatotroph pituitary tumor development. In addition to direct effects, estradiol-induced tumor formation may involve alterations in growth factor and cytokine production. We have studied whether estradiol stimulates the production of the angiogenic vascular endothelial growth factor and the potential tumor progression factor interleukin-6 in 5 lactotroph (LA) and 5 lactosomatotroph (LSA) human pituitary adenoma cell cultures. All tumors secreted heterogenous basal amounts of VEGF (18.0 +/- 1.4 to 425 +/- 26 pg/ml per 24 h) and IL-6 (18.1 +/- 1.5 to 604 +/- 17 pg/ml per 24 h). Estradiol (100 nM) significantly enhanced VEGF release in all LA and LSA cell cultures (47 to 168 % above basal). IL-6 secretion was stimulated in 3 out of 5 LA and in all LSA cell cultures (31 to 287 % above basal). In cell cultures obtained from tumors from which sufficient cells could be isolated, a dose-dependent effect of estradiol (1 to 100 nM) on VEGF and IL-6 production was observed. Stimulation of IL-6 and/or VEGF secretion by estradiol in the majority of human lactotroph and lactosomatotroph adenoma cell cultures studied, suggests that estrogens may contribute to adenoma expansion through the stimulation of these auto-/paracrine-acting adenoma progression factors.
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PMID:Estradiol stimulates vascular endothelial growth factor and interleukin-6 in human lactotroph and lactosomatotroph pituitary adenomas. 1475 67

The mean blood content of interleukin-6 in patients with adrenal tumors was much higher than in healthy donors. No correlations were revealed between interleukin-6 level, patients sex and age, stage and duration of the disease. Interleukin-6 concentration was maximum in patients with adrenocortical cancer. A negative correlation was found between interleukin-6 level and blood cortisol concentration in patients with cortisol-producing adenoma. In patients with aldosterone-producing adenoma, interleukin-6 level tended to correlate negatively with plasma renin activity.
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PMID:Serum interleukin-6 in patients with adrenal tumors. 1523 38

This is the first report of direct evidence that metanephric adenoma cells produce erythropoietin and other types of cytokines, which may be the cause of the high incidence of erythrocytosis in patients with this tumor. The purpose of the study was to establish a metanephric adenoma cell line in vitro from nephrectomized tumor tissue in order to investigate the ability of metanephric adenoma cells to produce erythropoietin and other types of cytokines. The tumor tissue was obtained from a 16-year-old boy who had developed metanephric adenoma with erythrocytosis and was served for cell culture. Significantly high concentrations of erythropoietin, granulocyte-macrophage colony-stimulating factor (GM-CSF), granulocyte-colony-stimulating factor (G-CSF), interleukin-6 (IL-6), and IL-8 were detected in the cell culture supernatant. Southern hybridization showed specific positive signals for GM-CSF, G-CSF, IL-6, IL-8 and erythropoietin. The number of chromosomes was 46-XY without any structural abnormalities in cytogenetic analysis of the cultured cells.
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PMID:Production of erythropoietin and multiple cytokines by metanephric adenoma results in erythrocytosis. 1761 Apr 79

The association between obesity and colorectal neoplasia may be mediated by inflammation. Circulating levels of C-reactive protein (CRP), interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-alpha) are elevated in the obese. Adipose tissue can produce and release the inflammatory cytokines that are potentially procarcinogenic. We examined circulating levels of CRP, IL-6, and TNF-alpha in relation to risk factors and the prevalence of colorectal adenomas. Plasma levels of CRP, IL-6, and TNF-alpha were quantified in 873 participants (242 colorectal adenoma cases and 631 controls) in a colonoscopy-based cross-sectional study conducted between 1998 and 2002. Multivariable logistic regression was used to estimate associations between known risk factors for colorectal neoplasia and circulating levels of inflammatory cytokines and associations between inflammatory cytokines and colorectal adenomas. Several known risk factors for colorectal neoplasia were associated with higher levels of inflammatory cytokines, including older age, current smoking, and increasing adiposity. The prevalence of colorectal adenomas was associated with higher concentrations of IL-6 and TNF-alpha and, to a lesser degree, with CRP. For IL-6, adjusted odds ratios (OR) for colorectal adenomas were 1.79 [95% confidence interval (CI), 1.19-2.69] for the second highest plasma level and 1.85 (95% CI, 1.24-2.75) for the highest level compared with the reference level. A similar association was found with TNF-alpha, with adjusted ORs of 1.56 (95% CI, 1.03-2.36) and 1.66 (95% CI, 1.10-2.52), respectively. Our findings indicate that systemic inflammation might be involved in the early development of colorectal neoplasia.
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PMID:Circulating levels of inflammatory cytokines and risk of colorectal adenomas. 1817 26


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