Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0020538 (hypertension)
 170,190 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Regardless of etiology, all cases of endogenous Cushing's syndrome are due to increased production of cortisol by the adrenal gland. Most are caused by adrenocorticotrophic hormone (ACTH)-secreting pituitary adenomas. Alternatively, the glucocorticoid excess may be due to adrenal neoplasia or to ectopic ACTH-secreting tumors. Cushing's syndrome is characterized by endocrine and metabolic alterations such as truncal obesity, hypertension, weakness, amenorrhea, hyperglycemia, osteoporosis and depression. Unless treated, the disease is associated with high morbidity, and ultimately, mortality. Depending on the etiology of Cushing's syndrome two different treatment modalities are possible: reduction of pituitary ACTH production or reduction of adrenocortical cortisol secretion. In the absence of efficient drug therapy, transsphenoidal resection of the pituitary adenoma is the primary treatment of choice for the reduction of ACTH secretion. In the last years there was much progress in understanding the molecular mechanisms that control the function of the hypothalamic-pituitary-adrenal axis. Thus, new insights made it possible to identify potential drug targets for the treatment of Cushing's syndrome. The present article reviews different drug targets and therapeutic options including drugs that control the central ACTH regulation, e.g. by modulating signaling pathways and transcriptional regulation of ACTH biosynthesis, corticotrophin releasing hormone (CRH) or glucocorticoid receptor antagonists, inhibitors of glucocorticoid synthesis, ketoconazole, somatostatin and dopamine analogs. Some of these substances might be useful for the treatment of Cushing's syndrome.
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PMID:New perspectives in the treatment of Cushing's syndrome. 1557 85

Hypertension is a serious health problem particularly for African-Americans. Previous studies have suggested that angiotensinogen (AGT) gene locus is involved in human essential hypertension. We have recently shown that an A/G polymorphism at -217 in the promoter of the AGT gene is associated with essential hypertension especially in African-Americans. We report here that A/G polymorphism at -217 affects the glucocorticoid-induced promoter activity of the human AGT gene. We show that recombinant glucocorticoid receptor (GR) binds strongly to the AGT gene promoter when nucleoside A is present at -217, and dexamethasone treatment increases the interleukin 6 induced promoter activity of reporter constructs containing nucleoside A at -217. Similarly cotransfection of GR and C/EBP beta or C/EBP delta increases the promoter activity of reporter construct containing nucleoside A at -217. Since AGT is an acute phase protein, we propose that increased expression of -217A allele of the AGT gene by glucocorticoids and C/EBP family of transcription factors may be involved in essential hypertension.
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PMID:A single-nucleotide polymorphism in human angiotensinogen gene is associated with essential hypertension and affects glucocorticoid induced promoter activity. 1563 May 92

Epidemiological evidence suggests that an adverse fetal environment permanently programs physiology, leading to increased risks of cardiovascular, metabolic, and neuroendocrine disorders in adulthood. Prenatal glucocorticoid excess or stress might link fetal maturation and adult pathophysiology. In a variety of animal models, prenatal glucocorticoid exposure or inhibition of 11beta-hydroxysteroid dehydrogenase type 2 (11beta-HSD2), the fetoplacental "barrier" to maternal glucocorticoids, reduces birth weight and causes permanent hypertension, hyperglycemia, and increased hypothalamic-pituitary-adrenal axis (HPA) activity and behavior resembling anxiety. In humans, 11beta-HSD2 gene mutations cause low birth weight and reduced placental 11beta-HSD2 activity associated with intrauterine growth retardation. Low birth weight babies have higher plasma cortisol levels throughout adult life, indicating HPA programming. The molecular mechanisms may reflect permanent changes in the expression of specific transcription factors; key is the glucocorticoid receptor itself. Differential programming of the glucocorticoid receptor in different tissues reflects effects upon one or more of the multiple tissue-specific alternate first exons/promoters of the glucocorticoid receptor gene. Overall, the data suggest that either pharmacological or physiological exposure to excess glucocorticoids prenatally programs pathologies in adult life.
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PMID:Glucocorticoid programming. 1567 96

The hypothalamic-pituitary-adrenal (HPA) axis plays important roles in maintaining alertness and modulating sleep. Dysfunction of this axis at any level (CRH receptor, glucocorticoid receptor, or mineralocorticoid receptor) can disrupt sleep. Herein, we review normal sleep, normal HPA axis physiology and circadian rhythm, the effects of the HPA axis on sleep, as well as the effects of sleep on the HPA axis. We also discuss the potential role of CRH in circadian-dependent alerting, aside from its role in the stress response. Two clinically relevant sleep disorders with likely HPA axis dysfunction, insomnia and obstructive sleep apnea, are discussed. In insomnia, we discuss how HPA axis hyperactivity may be partially causal to the clinical syndrome. In obstructive sleep apnea, we discuss how HPA axis hyperactivity may be a consequence of the disorder and contribute to secondary pathology such as insulin resistance, hypertension, depression, and insomnia. Mechanisms by which cortisol can affect slow wave sleep are discussed, as is the role the HPA axis plays in secondary effects of primary sleep disorders.
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PMID:On the interactions of the hypothalamic-pituitary-adrenal (HPA) axis and sleep: normal HPA axis activity and circadian rhythm, exemplary sleep disorders. 1572 14

Glucocorticoid resistance is a rare, familial or sporadic condition characterized by partial end-organ insensitivity to glucocorticoids. The clinical spectrum of the condition is broad, ranging from completely asymptomatic to severe hyperandrogenism and/or mineralocorticoid excess. The molecular basis of glucocorticoid resistance has been ascribed to mutations in the human glucocorticoid receptor-alpha (hGRalpha) gene, which impair one or more of the molecular mechanisms of GR action, thus altering tissue sensitivity to glucocorticoids. We identified a new case of generalized glucocorticoid resistance in a young woman who presented with a long-standing history of fatigue, anxiety, hyperandrogenism, and hypertension. The disease was caused by a novel, heterozygous mutation (T-->C) at nucleotide position 2318 (exon 9) of the hGRalpha gene, which resulted in substitution of leucine by proline at amino acid position 773 in the ligand-binding domain of the receptor. We systematically investigated the molecular mechanisms through which the natural hGRalphaL773P mutant impaired glucocorticoid signal transduction. Compared with the wild-type hGRalpha, hGRalphaL773P demonstrated a 2-fold reduction in the ability to transactivate the glucocorticoid-inducible mouse mammary tumor virus promoter, exerted a dominant negative effect on the wild-type receptor, had a 2.6-fold reduction in the affinity for ligand, showed delayed nuclear translocation (30 vs. 12 min), and, although it preserved its ability to bind to DNA, displayed an abnormal interaction with the GR-interacting protein 1 coactivator in vitro. We conclude that the carboxyl terminus of the ligand-binding domain of hGRalpha is extremely important in conferring transactivational activity by altering multiple functions of this composite transcription factor.
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PMID:A novel point mutation in the ligand-binding domain (LBD) of the human glucocorticoid receptor (hGR) causing generalized glucocorticoid resistance: the importance of the C terminus of hGR LBD in conferring transactivational activity. 1576 88

1. Hypertension is a serious risk factor for myocardial infarction, heart failure, vascular disease, stroke and renal failure. The incidence of hypertension is 25-30% in the adult Caucasian population and complications due to hypertension are even greater in African Americans. 2. The renin-angiotensin system plays an important role in the regulation of blood pressure and previous studies have suggested that angiotensinogen (AGT) gene locus is linked with human essential hypertension. Earlier studies suggested that a single nucleotide polymorphism (SNP) that converts methionine to threonine at amino acid 235 is associated with hypertension in the Caucasian population. However, this SNP is not associated with hypertension in African American and Chinese populations. 3. We have found an A/G polymorphism at -217 of the human AGT gene promoter and have shown that the frequency of allele A at -217 is significantly increased in the genomic DNA of African American hypertensive patients. 4. We have also shown that: (i) reporter constructs containing the AGT gene promoter with nucleoside A at -217 have increased promoter activity on transient transfection; and (ii) the CCAAT box enhancer binding protein (C/EBP) family of transcription factors and glucocorticoid receptor (GR) bind preferentially to this region of the promoter when nucleoside A is present at -217. In addition, variant -217A is always present with variants -532T, -793A and -1074T in the human AGT gene promoter. 5. These data suggest that the AGT haplotype containing -217A, -532T, -793A and -1074T may be involved in increased transcription of this gene and may play a role in human hypertension.
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PMID:A haplotype of the angiotensinogen gene is associated with hypertension in african americans. 1585 65

Patients with cortisol excess, Cushing's syndrome, develop a classical phenotype characterized by central obesity, hypertension, and increased cardiovascular mortality. Whilst this observation points to the importance of glucocorticoids, circulating cortisol excess is rare and does not explain the pathogenesis of many common conditions. At a tissue specific level, the enzyme 11beta-hydroxysteroid dehydrogenase type 1 (11beta-HSD1) locally regenerates active cortisol from inactive cortisone amplifying glucocorticoid receptor activation in the context of normal circulating cortisol levels. Increased 11beta-HSD1 activity and expression have been implicated in the pathogenesis of many common conditions including, obesity, insulin resistance, the metabolic syndrome, polycystic ovarian syndrome, osteoporosis and glaucoma. Furthermore, selective 11beta-HSD1 inhibition has been proposed as a novel therapeutic strategy in many of these conditions. Here we review the role of 11beta-HSD1 in human disease and discuss the impact of selective 11beta-HSD1 inhibition.
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PMID:11Beta-hydroxysteroid dehydrogenase type 1 in human disease: a novel therapeutic target. 1587 12

As obesity reaches epidemic levels in the United States there is an urgent need to understand the developmental pathways leading to this condition. Obesity increases the risk of hypertension and diabetes, symptoms of which are being seen with increased incidence in children. Adipocyte development begins in the fetus and, in contrast to all other tissues whose growth ceases in late juvenile life, it has the capacity for "unlimited" growth. In normal healthy individuals, the increase in fat mass with age is accompanied by a parallel increase in cortisol sensitivity, i.e., increased glucocorticoid receptor abundance and increased activity of the enzyme 11beta hydroxysteroid dehydrogenase type 1. Enhanced adipocyte sensitivity to cortisol is promoted in offspring born to mothers that were nutrient-restricted in utero in conjunction with increased peroxisome proliferator activated receptor alpha. This adaptation only appears to be associated with greater fat mass in the offspring when maternal nutrient restriction is confined to late gestation, coincident with the period of maximal fetal growth. In these offspring, increased fat mass is accompanied by glucose intolerance and insulin resistance, in conjunction with an adipose tissue specific reduction in glucose transporter 4 abundance. In conclusion, changes in maternal and, therefore, fetal nutrient supply at specific stages of gestation have the potential to substantially increase the risk of those offspring becoming obese in later life. The extent to which changes in dietary habits, both during pregnancy and in later life, may act to contribute to the current explosion in childhood and adult obesity remains a scientific and public health challenge to us all.
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PMID:Maternal nutritional programming of fetal adipose tissue development: long-term consequences for later obesity. 1618 15

Medroxyprogesterone acetate (MPA), a widely used synthetic progestational contraceptive, occasionally leads to Cushingoid side effects such as hypertension, fluid retention, and centripetal obesity. We investigated the effect of MPA on classic mineralocorticoid target genes, alpha-epithelial Na channel (ENaC) and sgk1, in the collecting duct. In adrenalectomized mice, aldosterone, dexamethasone, and MPA increased alpha-ENaC mRNA levels in kidney cortex. MPA and dexamethasone, but not progesterone, dose dependently increased alpha-ENaC and sgk1 mRNA in M-1 and in Madin-Darby canine kidney-C7 cells, both collecting duct cell lines. The stimulatory effect of MPA and dexamethasone on alpha-ENaC expression was inhibited by RU-38486, a combined glucocorticoid receptor (GR) and progesterone receptor (PR) antagonist, but not by Org31710, a pure PR antagonist. MPA and dexamethasone dose dependently increased alpha-ENaC promoter-driven luciferase activity in M-1 cells, which was not inhibited by Org31710, indicating that MPA regulates alpha-ENaC in a PR-independent manner. When tested in HT29 cells, MPA could only stimulate alpha-ENaC-driven reporter activity when GR was coexpressed, confirming the requirement for functional GR in the transcriptional effect of MPA. The activation of steroid receptors such as GR can explain the apparent glucocorticoid effects of MPA, independent of PR activation.
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PMID:Medroxyprogesterone acetate binds the glucocorticoid receptor to stimulate alpha-ENaC and sgk1 expression in renal collecting duct epithelia. 1618 95

Low birth weight is strongly predictive of hypertension, cardiovascular diseases, obesity, insulin resistance and diabetes. The mechanisms by which fetal undernutrition and, hence, low birth weight increase the risk of developing these diseases are unclear. To investigate the hypothesis of a primary defect in beta-cell development, we designed a rat model of undernutrition, involving an overall reduction in maternal food intake. In this model, fetuses with intrauterine growth retardation have a decreased beta-cell mass, which persists into adulthood and ultimately causes glucose intolerance, thereby mimicking features of the metabolic syndrome. Maternal undernutrition causes elevations in glucocorticoid concentrations, which, in turn, cause a reduction in beta-cell mass in the fetus. Our data also suggest a key role of glucocorticoids when nutrient supply is normal. By combining in-vitro studies with in-vivo investigations in mice lacking the glucocorticoid receptor in the whole organism or in specific pancreatic cell populations, we have shown that the glucocorticoid receptor is critical for ensuring pancreatic architecture and survival, as well as for beta-cell mass expansion during a critical developmental window. Glucocorticoids act on precursor cells before the onset of hormone gene expression and are likely to programme beta-cell differentiation by modifying the balance of specific transcription factors, mostly Pdx-1. Glucocorticoids should therefore be considered as important hormones in pancreatic development, in situations of both normal nutrition and undernutrition. To investigate whether this is also the case in human pancreatic development, we studied the expression of the glucocorticoid receptor and that of the transcription factor Pdx-1 on pancreatic specimens from very early to late stages of development of the human embryo. In terms of beta-cell ontogeny, expression of the glucocorticoid receptor in the pancreas coincides with that of the transcription factor Pdx-1 in beta cells. These results are consistent with a possible role for glucocorticoids during human pancreatic development.
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PMID:Nutrition, glucocorticoids and pancreas development. 1661 21


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