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)

Tetrahydrolipstatin (THL) is a selective inhibitor of fat absorption. In animal models, it has anti-obesity and anti-hypercholesterolemic activity and is presently in clinical trials for these indications. THL binds covalently to pancreatic lipase. Complete inhibition of lipolytic activity is obtained concomitant with the incorporation of 1 mol of THL/mol of enzyme. Pancreatic lipase is the best studied lipase, but published results concerning its catalytic mechanism are still controversial. In order to learn more about the inhibitory mechanism of THL, a selective lipase inhibitor interacting at or near the catalytic site, and therefore, to obtain more information on the catalytic mechanism of lipase, we have determined the amino acid residue to which THL is bound. After proteolytic degradation of porcine pancreatic lipase inhibited with radioactively labeled THL, the labeled peptides were isolated and analyzed by quantitative amino acid analysis, N-terminal sequencing, and by mass spectrometry with fast atom bombardment ionization. The data clearly show that THL is bound as an ester to the serine 152 of the lipase.
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PMID:The lipase inhibitor tetrahydrolipstatin binds covalently to the putative active site serine of pancreatic lipase. 189 34

Orlistat, a potent and selective inhibitor of gastrointestinal lipases, is designed for the treatment of obesity. The effect of orlistat on dietary fat absorption, when it was administered with diets differing in fibre content (high and low) and accessibility of fat (intra- and extracellular fat), was investigated in 32 hospitalized healthy males, according to an open, two-factorial study design. The subjects were randomly allocated to one of four parallel groups of equal size: A = intracellular fat, high fibre (28 g/day); B = extracellular fat, high fibre; C = extracellular fat, low fibre (9 g/day); or D = intracellular fat, low fibre. After a 5-day run-in period to accustom the volunteers to the standardized diet (2500 kcal and 84 g fat per day) and to establish baseline faecal fat parameters, they received 80 mg orlistat, three times daily mid-way through each meal for 8 days. Faeces were collected to measure total fat and free fatty acid excretions. The mean baseline-corrected excretion (% of dietary fat) in groups A, B, C and D, respectively, was 37.0, 30.4, 30.3 and 34.5 for total fat, and 6.5, 4.3, 2.6 and 3.9 for free fatty acids. The 95% confidence intervals for the difference between the means for high fibre and low fibre groups and for intracellular fat and extracellular fat groups, respectively, were 1.4 +/- 4.9 and 5.5 +/- 4.9 for total fat, and 2.2 +/- 3.1 and 1.9 +/- 3.1 for free fatty acids. The statistically significant difference (P < 0.05) in total faecal fat between intracellular fat and extracellular fat groups, in absolute terms < 5 g fat/day, was not regarded as clinically relevant. Under the conditions of this study, dietary fibre content and accessibility of fat had no relevant effect on the inhibition of fat absorption by orlistat.
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PMID:Influence of dietary composition on the inhibition of fat absorption by orlistat. 786 70

Orlistat is a potent and selective inhibitor of gastrointestinal lipases. The drug is designed for the treatment of obesity. The effect on dietary fat absorption of orlistat after administration of divided doses spread over 2 hours from mid-meal, in comparison with that after administration of a full dose mid-meal, was investigated in a randomized, single-blind study including 16 hospitalized healthy males. After a 5-day run-in, to accustom the subjects to a diet of 2350 kcal and 76 g fat per day and to establish baseline fecal fat excretion, subjects received, in two parallel groups of eight over 8 days, three times a day 80 mg orlistat at mid-meal, and placebo at mid-meal and 0.5, 1, and 2 hr after mid-meal (group A), or placebo at mid-meal, and 20 mg orlistat at mid-meal and 0.5, 1, and 2 hr after mid-meal (group B). Feces were collected to measure total fat excretion. The mean (SD) of fecal fat in percent of dietary fat, after deduction of pretreatment fecal fat, was (%) 36.1 (4.2) and 37.0 (9.3) in groups A and B, respectively. Changing the mode of administration of orlistat, within the dose regimens investigated, does not affect its pharmacologic efficacy.
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PMID:Comparison of the inhibition of dietary fat absorption by full versus divided doses of orlistat. 787 5

Orlistat, an inhibitor of gastrointestinal lipases, limits the absorption of ingested fat and could become a potential treatment for obesity. This analysis was performed to elucidate the relationship between orlistat dose and intensity of inhibition of dietary fat absorption (assessed by measuring fecal fat excretion). In 11 phase I double-blind, placebo-controlled, parallel-group randomized studies, a total of 171 subjects received oral daily doses that ranged from 30 to 1200 mg orlistat or matching placebo three times a day for 9 to 10 days. The results of the daily mean fecal fat excretion percentage (relative to ingested fat) were correlated to the orlistat daily dose. A simple maximum-effect model that included a basal value was used to fit the dose-response relationship for all evaluable subjects. The mean maximum percentage of ingested fat excreted in the feces was approximately 32% during orlistat administration compared with 5% during placebo administration. The orlistat daily dose that produced 50% of the maximum effect was 98 mg/day. The model-fitting suggests the existence of a steep portion of the dose-response curve up to approximately 400 mg/day, with a subsequent tendency to plateau at higher doses. Such an analysis was instrumental in identifying appropriate doses to be used in therapeutic trials for weight loss in obese patients.
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PMID:Retrospective population-based analysis of the dose-response (fecal fat excretion) relationship of orlistat in normal and obese volunteers. 803 98

Orlistat (Ro 18-0647) is an inhibitor of gastric, carboxylester and pancreatic lipase and specifically reduces the absorption of dietary fat due to the inhibition of triglyceride hydrolysis. Orlistat can be used for the treatment of obesity. Of 52 healthy obese patients entering a four-week single-blind run-in period with diet (500 kcal-reduced, containing 30% of calories in the form of fat) and placebo three times a day, 44 patients showed compliance to the diet by reducing their body weight by 0.5-4 kg from screening. These patients were randomized for a 12-week double-blind, parallel group, placebo-controlled treatment period with diet and 50 mg Orlistat or placebo three times a day. Complete data were available for 39 patients, 20 on Orlistat (3 men, 17 women; mean weight 85.5 +/- 12.1 kg; mean body mass index 30.6 +/- 3.7 kg/m2) and 19 on placebo (3 men, 16 women; mean weight 81.9 +/- 7.9 kg; mean body mass index 30.0 +/- 2.6 kg/m2. Total weight loss after randomization was 4.3 +/- 3.4 kg in the Orlistat group and 2.1 +/- 2.8 kg in the placebo group (P = 0.025, analysis of variance with repeated measurements; 95% confidence interval for the weight loss difference 0.2-4.2 kg). Gastrointestinal side effects were seen in the Orlistat group, but in most patients the symptoms were mild or transient. One patient dropped out because of faecal incontinence. No effect was seen on vitamin A levels, but vitamin E levels became lower in the Orlistat group (P < 0.05, paired t test).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Lipase inhibition: a novel concept in the treatment of obesity. 838 73

The effect of Orlistat, a lipase inhibitor used in the treatment of obesity was studied on gastrointestinal transit time, on body composition and on hormones known to be influenced by the degree of hydrolysis of nutritional triglycerides or by reduced nutrient intake and absorption. After a placebo run-in period 14 patients were randomized to a 12-week treatment period on Orlistat 360 mg per day (mean body weight 93.1 +/- 9.8 kg) or placebo (mean body weight 90.7 +/- 10.5 kg). At randomization and after 12 weeks body weight, body composition, thyroid hormones, catecholamines, insulin-like growth factor I (IGF-I) and IGF-binding protein 3 were measured. During 4 hours after consumption of a liquid fat-rich mixed meal containing study medication, 15 g lactulose and 25 g xylose, blood levels of glucose, insulin, c-peptide, glucagon, triglycerides, free fatty acids, cholecystokinin, pancreatic polypeptide and xylose and expiration air levels of hydrogen were measured. Weight loss was 4.2 +/- 3.5 kg in the Orlistat group versus 3.0 +/- 1.9 kg in the placebo group. Fat mass decreased to an equal degree, whereas lean body mass remained stable. No differences were found for thyroid hormones, catecholamines, IGF-I and IGFBP-3 levels. By comparing the areas under the curve (AUC) and the peak levels at randomization (acute effects) of insulin and c-peptide a tendency was found to be increased in the Orlistat group, whereas those of xylose were increased significantly, suggesting faster gastric emptying after Orlistat. No differences were found in the other parameters. By comparing the changes in responses (longer term effects) no significant differences were found. In conclusion, the presence in the gut of undigested and unabsorbed fat does not seem to have a relevant influence on hormonal status and body composition in a small group of moderately obese patients.
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PMID:Lipase inhibition and hormonal status, body composition and gastrointestinal processing of a liquid high-fat mixed meal in moderately obese subjects. 865 34

Lipase inhibition, leading to decreased intestinal fat adsorption can be used in the treatment of obesity. Orlistat, a lipase inhibitor, in a dose of 50 mg three times a day leads to a significant increase in weight loss compared to placebo in moderately obese people. These results are confirmed in a multiple-dose study using 10 mg, 60 mg and 120 mg Orlistat three times a day vs. placebo. The use of lipase inhibition has no significant influence on fasting levels of several hormonal systems, including thyroid hormones, catecholamines and IGF-I. The same is true for the responses of several gastrointestinal and pancreatic hormones after a liquid high-fat mixed meal. In general, Orlistat is tolerated very well, although a higher occurrence of gastrointestinal side effects is seen.
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PMID:First clinical studies with orlistat: a short review. 869 67

An open-label, placebo-controlled, randomized, two-way crossover study was performed in 12 healthy volunteers (between 20 and 44 years of age) to assess the effect of orlistat, a gastrointestinal lipase inhibitor that reduces dietary fat absorption and is being developed for weight control in obesity, on the absorption of vitamins A and E. Each participant received a single oral dose of 25,000 IU vitamin A followed 24 hours later by a single oral dose of 400 IU vitamin E on two separate occasions: during oral administration of 120 mg orlistat or placebo three times daily for 9 days. The two treatments were separated by a washout period of at least 2 weeks. Serial blood samples for pharmacokinetic analysis were collected at specified times over 24 hours after each dose of vitamin A for determination of serum concentrations of retinol, and over a period of 5 days after each dose of vitamin E for determination of serum concentrations of alpha-tocopherol, total cholesterol, and triglycerides. Orlistat significantly reduced the absorption of vitamin E (approximately 43% according to maximum concentration and approximately 60% according to area under the concentration-time curve), but not that of vitamin A, at the dose levels studied. The results of this study will aid in the implementation of a vitamin supplementation strategy, should vitamin deficiency occur in patients undergoing orlistat therapy.
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PMID:The effect of orlistat, an inhibitor of dietary fat absorption, on the absorption of vitamins A and E in healthy volunteers. 884 48

Orlistat (tetrahydrolipstatin) is an inhibitor of pancreatic and other lipases. As a pancreatic lipase inhibitor, it acts in the gastrointestinal lumen and is indicated for use in obesity. Serum total cholesterol and low density lipoprotein-cholesterol levels were reduced in obese, but otherwise healthy, patients during < or = 2 years' orlistat treatment; serum triglyceride and high density and very low density lipoprotein-cholesterol levels were unchanged in trials of < or = 12 weeks. Obese patients who were maintained on a hypocaloric diet and who received orlistat 360 mg/day for 12 weeks lost a significantly greater percentage of bodyweight than placebo recipients (5 vs 3.5%). In 2-year studies, weight loss was significantly greater in orlistat than in placebo recipients by the end of year 1; weight was further reduced or maintained in the second year, when a eucaloric diet was allowed, in orlistat but not placebo recipients. A greater proportion of orlistat than placebo recipients lost > 5% or > 10% of their initial bodyweight in 1- and 2-year studies.
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PMID:Orlistat. 971 48

The medical model of obesity treatment--combining diet, exercise, and behavior modification with antiobesity agents--suffered a setback when fenfluramine and dexfenfluramine were withdrawn from the market because of an association between these medications and valvular regurgitation. The Food and Drug Administration has recently approved sibutramine (Meridia), a norepinephrine and serotonin reuptake inhibitor that was originally developed as an antidepressant, but which has also been shown to reduce weight. In a 1-year placebo-controlled trial, 65% of patients receiving 15 mg sibutramine daily lost more than 5% of their body weight, compared with 29% of patients receiving a placebo; 39% of patients in the sibutramine group lost more than 10% of their body weight, compared with 8% of patients in the placebo group. Health benefits observed in patients receiving sibutramine include reductions in levels of triglycerides, uric acid, total cholesterol, and low-density lipoprotein (LDL) cholesterol and an increase in high-density lipoprotein (HDL) cholesterol levels. Another antiobesity drug currently under review by the Food and Drug Administration is orlistat (Xenical), a pancreatic lipase inhibitor that reduces the absorption of dietary fat by approximately 30%, thus reducing energy intake. In a 1-year placebo-controlled trial, 55% of patients receiving orlistat lost more than 5% of their body weight, and 25% lost more than 10% of their body weight, compared with 33% and 15%, respectively, of patients in the placebo group. In addition, orlistat slowed the rate of weight regain in the second year of treatment. Health benefits demonstrated in clinical trials of orlistat include reduced LDL cholesterol levels and increased levels of HDL cholesterol, reduced blood pressure and fasting insulin levels, improved oral glucose tolerance test outcomes, and improved glycemic control in obese patients with diabetes. The future of the pharmacologic treatment of obesity is promising. Many new antiobesity agents are in the early stages of development, and our understanding of the body's weight-regulating mechanisms is advancing steadily. Human trials of recombinant leptin are underway. Other promising compounds include those that block the Neuropeptide Y5 and Y1 (NY5, NY1) and Melanocortin-4 (MC4) receptors, stimulate uncoupling proteins, and unbind corticotrophin-releasing factor from its binding protein. As better medical treatments for obesity become available, the focus in dietary prescription may shift away from reducing energy intake toward healthier eating for disease prevention. At present, a comprehensive approach, which, in some patients, may include medical therapy as an adjunct, is necessary to treat obesity effectively.
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PMID:Modern medical management of obesity: the role of pharmaceutical intervention. 978 32


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