scholarly journals POMC Gene

2020 ◽  
Author(s):  
Keyword(s):  
Pomc Gene

P173 effects of tetrahydroisoquinolines on the POMC gene expression in anterior pituitary tumor cells

1994 ◽  
Vol 2 (1-2) ◽  
pp. 162
Author(s):  
I. Putscher ◽  
H. Haber ◽  
J. Fickel ◽  
A. Winkler ◽  
M. Melzig
Keyword(s):  
Gene Expression ◽  
Tumor Cells ◽  
Pituitary Tumor ◽  
Anterior Pituitary ◽  
Pomc Gene

scholarly journals Liver X Receptor-α Regulates Proopiomelanocortin (POMC) Gene Transcription in the Pituitary

2009 ◽  
Vol 23 (1) ◽  
pp. 47-60 ◽  
Author(s):  
Shunichi Matsumoto ◽  
Koshi Hashimoto ◽  
Masanobu Yamada ◽  
Teturou Satoh ◽  
Junko Hirato ◽  
...  
Keyword(s):  
Gene Transcription ◽  
Liver X Receptor ◽  
Liver X Receptor Α ◽  
Pomc Gene

The anorexigenic cytokine ciliary neurotrophic factor stimulates POMC gene expression via receptors localized in the nucleus of arcuate neurons

2012 ◽  
Vol 302 (4) ◽  
pp. E458-E467 ◽  
Author(s):  
Odile Couvreur ◽  
Alain Aubourg ◽  
Delphine Crépin ◽  
Jéril Degrouard ◽  
Arieh Gertler ◽  
...  
Keyword(s):  
Gene Expression ◽  
Cell Nucleus ◽  
Neurotrophic Factor ◽  
Energy Homeostasis ◽  
Ciliary Neurotrophic Factor ◽  
Hypothalamic Region ◽  
Diet Induced Obesity ◽  
Food Intake Regulation ◽  
Pomc Gene ◽  
Intake Regulation

Ciliary neurotrophic factor (CNTF) is a neural cytokine that reduces appetite and body weight when administrated to rodents or humans. We have demonstrated recently that the level of CNTF in the arcuate nucleus (ARC), a key hypothalamic region involved in food intake regulation, is positively correlated with protection against diet-induced obesity. However, the comprehension of the physiological significance of neural CNTF action was still incomplete because CNTF lacks a signal peptide and thus may not be secreted by the classical exocytosis pathways. Knowing that CNTF distribution shares similarities with that of its receptor subunits in the rat ARC, we hypothesized that CNTF could exert a direct intracrine effect in ARC cells. Here, we demonstrate that CNTF, together with its receptor subunits, translocates to the cell nucleus of anorexigenic POMC neurons in the rat ARC. Furthermore, the stimulation of hypothalamic nuclear fractions with CNTF induces the phosphorylation of several signaling proteins, including Akt, as well as the transcription of the POMC gene. These data strongly suggest that intracellular CNTF may directly modulate POMC gene expression via the activation of receptors localized in the cell nucleus, providing a novel plausible mechanism of CNTF action in regulating energy homeostasis.

Influence of photoperiod and gonadal status on food intake, adiposity, and gene expression of hypothalamic appetite regulators in a seasonal mammal

2007 ◽  
Vol 292 (1) ◽  
pp. R242-R252 ◽  
Author(s):  
Chantacha Anukulkitch ◽  
Alexandra Rao ◽  
Frank R. Dunshea ◽  
Dominique Blache ◽  
Gerald A. Lincoln ◽  
...  
Keyword(s):  
Gene Expression ◽  
Food Intake ◽  
Arcuate Nucleus ◽  
Leptin Receptor ◽  
Reproductive Axis ◽  
Pomc Gene ◽  
Gonadal Status ◽  
Long Photoperiod ◽  
Refractory Phase

We studied the effects of photoperiod on metabolic profiles, adiposity, and gene expression of hypothalamic appetite-regulating peptides in gonad-intact and castrated Soay rams. Groups of five to six animals were studied 6, 18, or 30 wk after switching from long photoperiod (LP: 16 h of light) to short photoperiod (SP: 8 h of light). Reproductive and metabolic indexes were measured in blood plasma. Expression of neuropeptide Y (NPY), proopiomelanocortin (POMC), and leptin receptor (ObRb) in the arcuate nucleus was measured using in situ hybridization. Testosterone levels of intact animals were low under LP, increased to a peak at 16 wk under SP, and then declined. Voluntary food intake (VFI) was high under LP in both intact and castrated animals, decreased to a nadir at 12–16 wk under SP, and then recovered, but only in intact rams as the reproductive axis became photorefractory to SP. NPY gene expression varied positively and POMC expression varied negatively with the cycle in VFI, with differences between intact and castrate rams in the refractory phase. ObRb expression decreased under SP, unrelated to changes in VFI. Visceral fat weight also varied between the intact and castrated animals across the cycle. We conclude that 1) photoperiodic changes in VFI reflect changes in NPY and POMC gene expression, 2) changes in ObRb gene expression are not necessarily determinants of changes in VFI, 3) gonadal status affects the pattern of VFI that changes with photoperiod, and 4) in the absence of gonadal factors, animals can eat less but gain adiposity.

scholarly journals Ectopic corticotroph syndrome

2004 ◽  
Vol 132 (1-2) ◽  
pp. 28-32 ◽  
Author(s):  
Zorana Penezic ◽  
Slavica Savic ◽  
Svetlana Vujovic ◽  
Svetislav Tatic ◽  
Maja Ercegovac ◽  
...  
Keyword(s):  
Cushing’S Syndrome ◽  
Cushing's Syndrome ◽  
Carcinoid Tumors ◽  
Neuroendocrine Cells ◽  
Ectopic Acth Syndrome ◽  
High Dose ◽  
Pituitary Cells ◽  
Acth Secretion ◽  
Ectopic Acth ◽  
Pomc Gene

INTRODUCTION Endogenous Cushing's syndrome is a clinical state resulting from prolonged, inappropriate exposure to excessive endogenous secretion of Cortisol and hence excess circulating free cortisol, characterized by loss of the normal feedback mechanisms of the hypothalamo-pituitary-adrenal axis and the normal circadian rhythm of cortisol secretion [2]. The etiology of Cushing's syndrome may be excessive ACTH secretion from the pituitary gland, ectopic ACTH secretion by nonpituitary tumor, or excessive autonomous secretion of cortisol from a hyperfunctioning adrenal adenoma or carcinoma. Other than this broad ACTH-dependent and ACTH-independent categories, the syndrome may be caused by ectopic CRH secretion, PPNAD, MAH, ectopic action of GIP or catecholamines, and other adrenel-dependent processes associated with adrenocortical hyperfunction. CASE REPORT A 31 year-old men with b-month history of hyperpigmentation, weight gain and proximal myopathy was refereed to Institute of Endocrinology for evaluation of hypercortisolism. At admission, patient had classic cushingoid habit with plethoric face, dermal and muscle atrophy, abdominal strie rubrae and centripetal obesity. The standard laboratory data showed hyperglycaemia and hypokaliemia with high potassium excretion level. The circadian rhythm of cortisol secretion was blunted, with moderately elevated ACTH level, and without cortisol suppression after low-dose and high-dose dexamethason suppression test. Urinary 5HIAA was elevated. Abdominal and sellar region magnetic resonance imaging was negative. CRH stimulation resulted in ACTH increase of 87% of basal, but without significant increase of cortisol level, only 7%. Thoracal CT scan revealed 14 mm mass in right apical pulmonary segment. A wedge resection of anterior segment of right upper lobe was performed. Microscopic evaluation showed tumor tissue consisting of solid areas of uniform, oval cells with eosinophilic cytoplasm and centrally located nuclei. Stromal tissue was scanty, and mitotic figures were infrequent. Tumor cells were immunoreactive for synaptophysin, neuron-specific enolase, and ACTH. The postoperative course was uneventful and the patient was discharged on glucocorticoid supplementation. Signs of Cushing's syndrome were in regression, and patient remained normotensive and normoglycaemic without therapy. DISCUSSION A multitude of normal nonpituitary cells from different organs and tissues have been shown to express the POMC gene from which ACTH is derived. The tumors most commonly associated the ectopic ACTH syndrome arise from neuroendocrine tissues, APUD cells. POMC gene expression in non-pituitary cells differs from that in pituitary cells both qualitatively and quantitatively [8], Aggressive tumors, like small cell cancer of the lung (SCCL) preferentially release intact POMC, whereas carcinoids rather overprocess the precursor, releasing ACTH and smaller peptides like CLIP. Some tumors associated with ectopic ACTH syndrome express other markers of neuroendocrine differentiation like two specific prohormone convertases (PCs). Assessment of vasopressin (V3) receptor gene expression in ACTH-producing nonpituitary tumors revealed bronchial carcinoid as a particular subset of tumors where both V3 receptor and POMC gene may be expressed in pattern indistinguishable from that in corticotroph adenoma [9]. In most, but not all, patients with ectopic ACTH syndrome, cortisol is unresponsive to high-dose dexamethason suppression test, what is used as diagnostic tool. It is not clear if the primary resistance resulted from structural abnormality of the native glucocorticoid receptor (GR), a low level of expression, or some intrinsic property of the cell line [9]. It appears that ectopic ACTH syndrome is made of two different entities. When it is because of highly differentiated tumors, with highest level of pituitary-like POMC mRNA, expressing PCs, high level of V3 receptors and GR, like bronchial carcinoids, it might be called ectopic corticotroph syndrome. In contrast, when it is caused by aggressive, poorly differentiated tumors, with much lower expression of V3 receptor, like SCCL, it might be called aberrant ACTH secretion syndrome. Carcinoid tumors have been reported in a wide range of organs but most commonly involve the lungs, bronchi, and gastrointestinal tract. They arise from neuroendocrine cells and are characterized by positive reactions to markers of neuroendocrine tissue, including neuron specific enolase, synaptophysin, and chromogranina [11]. Carcinoid tumors are typically found to contain numerous membrane-bound neurosecretory granules composed of variety of hormones and biogenic amines. One of the best characterized is serotonin, subsequently metabolized to 5-hydrohy-indolacetic acid (5-HIAA), which is excreted in the urine. In addition to serotonin, carcinoid tumors have been found to secrete ACTH, histamine, dopamine, substance P, neurotensin, prostaglandins and kallikrein. The release of serotonin and other vasoactive substances is thought to cause carcinoid syndrome, which manifestations are episodic flushing, weezing, diarrhea, and eventual right-sided valvular heart disease. These tumors have been classified as either well-differentiated or poorly differentiated neuroendocrine carcinomas. The term ?pulmonary tumorlets" describes multiple microscopic nests of neuroendocrine cells in the lungs [12]. Pulmonary carcinoids make up approximately 2 percents of primary lung tumors. The majority of these tumors are perihilar in location, and patients often presents with recurrent pneumonia, cough, hemoptisis, or chest pain. The carcinoid syndrome occurs in less than 5 percent of cases. Ectopic secretion of ACTH from pulmonary carcinoid accounts for 1 percent of all cases of Cushing's syndrome. They are distinct clinical and pathologic entity, generally peripheral in location. Although they are usually typical by standard histologie criteria, they have mush greater metastatic potential than hormonally quiescent typical carcinoids [13]. Surgical treatment therefore should be one proposed for more aggressive malignant tumors. In all cases of ACTH-dependent Cushing's syndrome with regular pituitary MRI and bilateral inferior petrosal sinus sampling, thin-section and spiral CT scanning of the chest should be routine diagnostic procedure [14], We present thirty-one year old patient with typical pulmonary carcinod with ACTH ectopic secretion consequently confirmed by histology.

scholarly journals Hormonally mediated negative regulation of human pro-opiomelanocortin gene expression after transfection into mouse L cells.

1985 ◽  
Vol 5 (9) ◽  
pp. 2443-2453 ◽  
Author(s):  
A Israel ◽  
S N Cohen
Keyword(s):  
Simian Virus 40 ◽  
Simian Virus ◽  
Negative Regulation ◽  
Coding Region ◽  
Transient Expression Assay ◽  
S1 Nuclease ◽  
Protein Coding ◽  
Pomc Gene ◽  
Simplex Virus ◽  
Nuclease Mapping

We report results indicating that expression and hormonally controlled negative regulation of the human pro-opiomelanocortin (POMC) gene in mouse fibroblasts can be accomplished by the placement nearby of a simian virus 40 enhancer sequence. Expression resulting from correctly initiated transcription required the enhancer in cis both in cells stably transfected with the POMC gene and in a transient expression assay with constructs that fused that POMC promoter region to the protein-coding region of the herpes simplex virus thymidine kinase (TK) gene. Negative regulation of POMC transcription by glucocorticoids was demonstrated in transiently infected cells by assaying for TK activity encoded by the POMC-TK fusion constructs and by quantitative S1 nuclease mapping. The sequences responsible for such regulation were shown to be contained within a DNA segment that extends 670 base pairs upstream from the cap site for POMC mRNA.

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