Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0028754 (obesity)
 124,988 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The pathogenesis of the rare hypernatremia, usually described in the literature as "neurogenic" or "essential" hypernatremia, consists of defective thirst mechanism either alone or in combination with impaired osmoregulation of ADH release. As etiology, disturbances of the neoplastic, vascular and degenerative type and malformations in the hypothalamic area are known. In patients with the hypodipsia-hypernatremia syndrome, dysfunction of the anterior pituitary lobe, obesity, abnormal regulation of body temperature, psychomotor retardation and episodic muscular weakness are frequently encountered as additional abnormalities. A 6-year-old patient is described with hypodipsia-hypernatremia syndrome manifest for 3 years. Besides hypernatremia, hypodipsia and the relative insensitivity of the osmoreceptors regulating ADH release, elevated body temperature, polyphagia and obesity, partial hypothalamic-hypophyseal dysfunction, lethargy and psychomotor retardation are the principal findings. An inflammatory lesion or one occupying an intracranial space was not demonstrable until now. Under forced water intake and hypocaloric diet the patient has progressed well with nearly complete normalization of the hypernatremia, body temperature and obesity.
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PMID:Hypodipsia-hypernatremia syndrome. 42 94

A 62-year-old male with small cell lung cancer (SCLC) associated with Cushing's syndrome and diabetes insipidus (DI) is reported. The patient was referred to our hospital for treatment of SCLC. A diagnosis of paraneoplastic Cushing's syndrome was made on the basis of an elevated serum ACTH (623.5 pg/ml) level, elevated excretion of urinary 17-OHCS (18.01 mg/day), obesity, hypertension, hyperglycemia, persistent hypokalemia, alkalosis, and no history of diabetes mellitus. He was also diagnosed as having DI based on polyuria and polydipsia, low specific gravity of the urine (1.007-1.010), low serum ADH (1.4 pg/ml) level, normal plasma osmolarity (29 mOsm/kg H2O), and the results of water deprivation test. DI and a left visual field defect was suggestive of metastasis to the pituitary region, but no lesion was detected by either CT scan or MRI scan. The patient failed to show a good response to intensive chemotherapy, and died of the tumor five months after commencing chemotherapy. Post-mortem examination revealed metastases to the hypothalamic-neurohypophyseal region, lungs, liver, adrenal glands, bone, bone marrow, and hilar and mediastinal lymph nodes.
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PMID:[A case of small cell lung cancer associated with diabetes insipidus and Cushing's syndrome]. 839 May 89

Considerable variation in offspring outcome occurs following intrauterine ethanol exposure. The mechanism underlying this varying susceptibility may involve genetic differences in ethanol metabolism catalyzed by alcohol dehydrogenase (ADH) and cytochrome P450 2E1 (CYP2E1). A recent population study demonstrated a protective role for the ADH-beta(3) isoform, which is encoded by ADH2*3, an allele unique to African Americans. Drinking during pregnancy was associated with lower scores on the Bayley Scales of Infant Developmental Mental Index (MDI), but only in the offspring of mothers without an ADH2*3 allele. Lower MDI scores were associated with the three-way interaction among increasing ethanol intake and maternal and offspring absence of the ADH2*3 allele (p < 0.01, analysis of variance, model r(2) = 0.09). The protection afforded by this allele is likely secondary to its encoding of the high K(m), high V(max) ADH-beta3 isoenzyme, which would provide more efficient ethanol metabolism at high blood ethanol concentrations. However, the small amount of variance accounted for by the ADH2 polymorphism suggests that other genetic and/or environmental factors are also determinants of offspring risk. We recently described a 96-bp insertion polymorphism in the CYP2E1 regulatory region that is associated with enhanced CYP2E1 metabolic ability in the presence of ethanol intake or obesity, conditions associated with CYP2E1 induction (p < 0.01, both). The frequency of the insertion varies across ethnic groups, occurring in about 30% of African Americans and 7% of Caucasians (p < 0.01), and is sufficiently common to impact susceptibility to alcohol-related birth defects. Thus, genetic differences in ADH and CYP2E1 are likely determinants of offspring risk.
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PMID:ADH2 and CYP2E1 genetic polymorphisms: risk factors for alcohol-related birth defects. 1125 52

Short-chain dehydrogenases/reductases (SDR) form a large, functionally heterogeneous protein family presently with about 3000 primary and about 30 3D structures deposited in databases. Despite low sequence identities between different forms (about 15-30%), the 3D structures display highly similar alpha/beta folding patterns with a central beta-sheet, typical of the Rossmann-fold. Based on distinct sequence motifs functional assignments and classifications are possible, making it possible to build a general nomenclature system. Recent mutagenetic and structural studies considerably extend the knowledge on the general reaction mechanism, thereby establishing a catalytic tetrad of Asn-Ser-Tyr-Lys residues, which presumably form the framework for a proton relay system including the 2'-OH of the nicotinamide ribose, similar to the mechanism found in horse liver ADH. Based on their cellular functions, several SDR enzymes appear as possible and promising pharmacological targets with application areas spanning hormone-dependent cancer forms or metabolic diseases such as obesity and diabetes, and infectious diseases.
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PMID:Short-chain dehydrogenases/reductases (SDR): the 2002 update. 1260 10

Dyslipidemia and obesity are common in adult patients with hypopituitarism. Possible contributions of age, sex and hormone deficiencies to hypercholesterolemia and obesity in adult hypopituitary patients were analyzed in 1, 272 Japanese cases based on a database of a national survey on adult hypopituitarism. In patients on routine hormone replacement therapy, 30.5% of male and 40.7% of female subjects were considered hypercholesterolemic. In univariate analysis, hypercholesterolemia was more prevalent in female, aged, untreated Gn-deficient and TSH-deficient groups. In multivariate analysis, sex of female, age older than 40 yr and TSH deficiency were the independent contributing factors to hypercholesterolemia. Obesity (body mass index (BMI) > or = 25 kg/m2) was more prevalent in male, TSH-deficient and ADH-deficient groups. Severe obesity (BMI > or = 30) was observed in high prevalence in the youngest group. These findings suggest that hypercholesterolemia and obesity were prevalent in different age and gender groups in Japanese adult patients with hypopituitarism. Insufficient replacement of thyroid hormone and possibly gonadotropin deficiency might contribute to hypercholesterolemia. In contrast, hypothalamic dysfunction as well as hormone deficiencies might play roles in obesity in these patients.
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PMID:Hypercholesterolemia and obesity in adult patients with hypopituitarism: a report of a nation-wide survey in Japan. 1470 49

Oxidation of ethanol via alcohol dehydrogenase (ADH) explains various metabolic effects of ethanol but does not account for the tolerance. This fact, as well as the discovery of the proliferation of the smooth endoplasmic reticulum (SER) after chronic alcohol consumption, suggested the existence of an additional pathway which was then described by Lieber and DeCarli, namely the microsomal ethanol oxidizing system (MEOS), involving cytochrome P450. The existence of this system was initially challenged but the effect of ethanol on liver microsomes was confirmed by Remmer and his group. After chronic ethanol consumption, the activity of the MEOS increases, with an associated rise in cytochrome P450, especially CYP2E1, most conclusively shown in alcohol dehydrogenase negative deer mice. There is also cross-induction of the metabolism of other drugs, resulting in drug tolerance. Furthermore, the conversion of hepatotoxic agents to toxic metabolites increases, which explains the enhanced susceptibility of alcoholics to the adverse effects of various xenobiotics, including industrial solvents. CYP2E1 also activates some commonly used drugs (such as acetaminophen) to their toxic metabolites, and promotes carcinogenesis. In addition, catabolism of retinol is accelerated resulting in its depletion. Contrasting with the stimulating effects of chronic consumption, acute ethanol intake inhibits the metabolism of other drugs. Moreover, metabolism by CYP2E1 results in a significant release of free radicals which, in turn, diminishes reduced glutathione (GSH) and other defense systems against oxidative stress which plays a major pathogenic role in alcoholic liver disease. CYP1A2 and CYP3A4, two other perivenular P450s, also sustain the metabolism of ethanol, thereby contributing to MEOS activity and possibly liver injury. CYP2E1 has also a physiologic role which comprises gluconeogenesis from ketones, oxidation of fatty acids, and detoxification of xenobiotics other than ethanol. Excess of these physiological substrates (such as seen in obesity and diabetes) also leads to CYP2E1 induction and nonalcoholic fatty liver disease (NAFLD), which includes nonalcoholic fatty liver and nonalcoholic steatohepatitis (NASH), with pathological lesions similar to those observed in alcoholic steatohepatitis. Increases of CYP2E1 and its mRNA prevail in the perivenular zone, the area of maximal liver damage. CYP2E1 up-regulation was also demonstrated in obese patients as well as in rat models of obesity and NASH. Furthermore, NASH is increasingly recognized as a precursor to more severe liver disease, sometimes evolving into "cryptogenic" cirrhosis. The prevalence of NAFLD averages 20% and that of NASH 2% to 3% in the general population, making these conditions the most common liver diseases in the United States. Considering the pathogenic role that up-regulation of CYP2E1 also plays in alcoholic liver disease (vide supra), it is apparent that a major therapeutic challenge is now to find a way to control this toxic process. CYP2E1 inhibitors oppose alcohol-induced liver damage, but heretofore available compounds are too toxic for clinical use. Recently, however, polyenylphosphatidylcholine (PPC), an innocuous mixture of polyunsaturated phosphatidylcholines extracted from soybeans (and its active component dilinoleoylphosphatidylcholine), were discovered to decrease CYP2E1 activity. PPC also opposes hepatic oxidative stress and fibrosis. It is now being tested clinically.
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PMID:The discovery of the microsomal ethanol oxidizing system and its physiologic and pathologic role. 1555 33

Liver disease in the alcoholic is due not only to malnutrition but also to ethanol's hepatotoxicity linked to its metabolism by means of the alcohol dehydrogenase and cytochrome P450 2E1 (CYP2E1) pathways and the resulting production of toxic acetaldehyde. In addition, alcohol dehydrogenase-mediated ethanol metabolism generates the reduced form of nicotinamide adenine dinucleotide (NADH), which promotes steatosis by stimulating the synthesis of fatty acids and opposing their oxidation. Steatosis is also promoted by excess dietary lipids and can be attenuated by their replacement with medium-chain triglycerides. Through reduction of pyruvate, elevated NADH also increases lactate, which stimulates collagen synthesis in myofibroblasts. Furthermore, CYP2E1 activity is inducible by its substrates, not only ethanol but also fatty acids. Their excess and metabolism by means of this pathway generate release of free radicals, which cause oxidative stress, with peroxidation of lipids and membrane damage, including altered enzyme activities. Products of lipid peroxidation such as 4-hydroxynonenal stimulate collagen generation and fibrosis, which are further increased through diminished feedback inhibition of collagen synthesis because acetaldehyde forms adducts with the carboxyl-terminal propeptide of procollagen in hepatic stellate cells. Acetaldehyde is also toxic to the mitochondria, and it aggravates their oxidative stress by binding to reduced glutathione and promoting its leakage. Oxidative stress and associated cellular injury promote inflammation, which is aggravated by increased production of the proinflammatory cytokine tumor necrosis factor-alpha in the Kupffer cells. These are activated by induction of their CYP2E1 as well as by endotoxin. The endotoxin-stimulated tumor necrosis factor-alpha release is decreased by dilinoleoylphosphatidylcholine, the active phosphatidylcholine (PC) species of polyenylphosphatidylcholine (PPC). Moreover, defense mechanisms provided by peroxisome proliferator-activated receptor alpha and omega fatty acid oxidation are readily overwhelmed, particularly in female rats and also in women who have low hepatic induction of fatty acid-binding protein (L-FABPc). Accordingly, the intracellular concentration of free fatty acids may become high enough to injure membranes, thereby contributing to necrosis, inflammation, and progression to fibrosis and cirrhosis. Eventually, hepatic S-adenosylmethionine and PCs become depleted in the alcoholic, with impairment of their multiple cellular functions, which can be restored by PC replenishment. Thus, prevention and therapy opposing the development of steatosis and its progression to more severe injury can be achieved by a multifactorial approach: control of alcohol consumption, avoidance of obesity and of excess dietary long-chain fatty acids, or their replacement with medium-chain fatty acids, and replenishment of S-adenosylmethionine and PCs by using PPC. Progress in the understanding of the pathogenesis of alcoholic fatty liver and its progression to inflammation and fibrosis has resulted in prospects for their better prevention and treatment.
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PMID:Alcoholic fatty liver: its pathogenesis and mechanism of progression to inflammation and fibrosis. 1567 Jun 60

Although the vast majority of heavy drinkers and individuals with obesity, insulin resistance, and the metabolic syndrome have steatosis, only a minority ever develop steatohepatitis, fibrosis, and cirrhosis. Genetic and environmental risk factors for advanced alcoholic liver disease (ALD) and nonalcoholic fatty liver disease (NAFLD) seem likely to include factors that influence the severity of steatosis and oxidative stress, the cytokine milieu, the magnitude of the immune response, and/or the severity of liver fibrosis. For ALD, the dose and pattern of alcohol intake, coffee intake, and dietary and other lifestyle factors leading to obesity are the most important environmental determinants of disease risk. For NAFLD, dietary saturated fat and antioxidant intake, small bowel bacterial overgrowth, and obstructive sleep apnea syndrome may play a role. Family studies and interethnic variations in susceptibility suggest that genetic factors are important in determining disease risk. For ALD, functional polymorphisms in the ADH and ALDH alcohol metabolizing genes play a role in determining susceptibility in Oriental populations. No genetic associations with advanced NAFLD have been replicated in large studies. Preliminary data suggest that polymorphisms in the genes encoding microsomal triglyceride transfer protein, superoxide dismutase 2, the CD14 endotoxin receptor, tumor necrosis factor alpha, transforming growth factor beta, and angiotensinogen may be associated with steatohepatitis or hepatic fibrosis or both.
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PMID:Genetics of alcoholic liver disease and nonalcoholic fatty liver disease. 1729 76

Despite remarkable progress in diagnosis and understanding of risk factors, cardiovascular disease (CVD) remains still the leading cause of morbidity and mortality in the world's developed countries. The metabolic syndrome, a cluster of risk factors (visceral obesity, insulin resistance, dyslipidaemia, and hypertension), is increasingly being recognized as a new risk factor for type 2 diabetes and atherosclerotic cardiovascular disease. Nevertheless, there is wide variation in both the occurrence of disease and age of onset, even in individuals who display very similar risk profiles. There is now compelling evidence that a complex interplay between genetic determinants and environmental factors (still largely unknown) is the reason for this large inter-individual variation in disease susceptibility. The purpose of the present review is to describe the current status of our knowledge concerning the gene-environment interactions potentially implicated in the pathogenesis of metabolic syndrome, diabetes and cardiovascular disease. It focuses predominantly on studies of genes (peroxisome proliferator-activated receptor-gamma, alcohol dehydrogenase type 1C, apolipoprotein E, glutathione S-transferases T1 and M1) that are known to be modified by dietary and lifestyle habits (fat diet, intake of alcohol and smoking habit). It also describes the limited current understanding of the role of genetic variants of xenobiotic metabolizing enzymes and their interactions with environmental toxicants. Additional studies are needed in order to clarify whether inter-individual differences in detoxification of environmental toxicants may have an essential role in the development of CVD and contribute to the emerging field of "environmental cardiology". Such knowledge may be particularly relevant for improving cardiovascular risk stratification and conceiving the development of "personalized intervention program".
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PMID:Metabolic syndrome, diabetes and atherosclerosis: influence of gene-environment interaction. 1902 10

The constant supply of oxygen and nutriments to cells (especially neurons) is the role of the cardiovascular system. The constant supply of water (and sodium) for cardiovascular function is the role of thirst and sodium appetite and kidney function. This physiological regulation ensures that plasma volume and osmolality are maintained within set limits by initiating behaviour and release of hormones necessary to ingest and conserve water and sodium within the body. This regulation is separated into 2 parts; intracellular and extracellular (blood). An increased osmolality draws water from cells into the blood thus dehydrating specific brain osmoreceptors that stimulate drinking and release of anti diuretic hormone (ADH or vasopressin). ADH reduces water loss via lowered urine volume. Extracellular dehydration (hypovolaemia) stimulates specific vascular receptors that signal brain centres to initiate drinking and ADH release. Baro/volume receptors in the kidney participate in stimulating the release of the enzyme renin that starts a cascade of events to produce angiotensin II (AngII), which initiates also drinking and ADH release. This stimulates also aldosterone release which reduces kidney loss of urine sodium. Both AngII and ADH are vasoactive hormones that could work to reduce blood vessel diameter around the remaining blood. All these events work in concert so that the cardiovascular system can maintain a constant perfusion pressure, especially to the brain. Even if drinking does not take place ADH, AngII and aldosterone are still released. Furthermore, it has been observed that treatment of hypertension, obesity, diabetes and cancer can involve renin-AngII antagonists which could suggest that, in humans at least, there may be dysfunction of the thirst regulatory mechanism.
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PMID:Thirst and hydration: physiology and consequences of dysfunction. 2021 37


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