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Query: UMLS:C0028754 (obesity)
 124,988 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Black-white differences in serum triglycerides and high-density lipoprotein (HDL) cholesterol concentrations are known. However, the metabolic basis for these differences is not clear. This study determined the magnitude of postprandial triglyceride concentrations, lipoprotein lipase and hepatic triglyceride lipase activities in postheparin plasma, and serum lipid and lipoprotein cholesterol concentrations in healthy young adult black men (n = 22) and white men (n = 28). Postprandial triglyceride concentrations were measured at 2, 3, 4, 5, 6, and 8 hours after a standardized test meal. Serum lipid and lipoprotein cholesterol concentrations were similar between the races in this study sample. However, incremental (above basal) increases in triglycerides were significantly greater in white men versus black men at 2 hours (P = .01) and tended to be greater at 3 hours (P = .12) and 4 hours (P = .06) after the fat load. In a multivariate analysis that included age, race, apolipoprotein E (apoE) genotype, fasting triglycerides, obesity measures, alcohol intake, and cigarette use, fasting triglycerides (P = .04) and, to a lesser extent, race (P = .07) were associated independently with the 2-hour incremental increase in triglycerides. The incremental triglyceride response correlated inversely with HDL cholesterol in both whites (r = -.38, P = .04) and blacks (r = -.59, P = .004). Lipoprotein lipase activity was higher (P = .049) and hepatic triglyceride lipase activity lower (P = .0001) in black men compared with white men; racial differences persisted after adjusting for the covariates. While lipoprotein lipase activity tended to associate inversely with the postprandial triglyceride concentration in both races, hepatic triglyceride lipase activity tended to correlate positively in whites and inversely in blacks. These results suggest that compared with whites, blacks may have an efficient lipid-clearing mechanism that could explain the black-white differences in lipoproteins found in the population at large.
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PMID:Black-white differences in postprandial triglyceride response and postheparin lipoprotein lipase and hepatic triglyceride lipase among young men. 1038 Nov 50

The purpose of this study was to determine the relationship between insulin resistance and apoB100 metabolism in African American males. Fifteen subjects, 33 +/- 7.6 years old, were divided into two groups, insulin-resistant (IR) or insulin-sensitive (IS), based on the sum of the plasma insulin concentrations during an oral glucose tolerance test. The IR group (n = 8) differed significantly from the IS group (n = 7) with respect to body mass index (BMI) (30.1 vs 23.1 kg/m2; P = 0.0003), fasting triglycerides, (118 vs 54 mg/dl, P = 0. 013), and total plasma apolipoprotein B100 (80 vs 59 mg/dl, P = 0.014). Significantly elevated apoB100 levels in the IR group were seen in very low density lipoprotein (VLDL) (5.1 vs 3.4 mg/dl, P = 0.045) and intermediate density lipoprotein (IDL) (18 vs 12 mg/dl, P = 0.017) but not in low density lipoprotein (LDL) (57 vs 46 mg/dl, P = 0.19). Total cholesterol, high density lipoprotein cholesterol (HDL-C), low density lipoprotein cholesterol (LDL-C), apolipoprotein A-I, and blood pressure were not significantly different between the two groups. There was a high correlation between the sum of insulins during the oral glucose tolerance test and the BMI (rho = 0.88, P = 0.0001). In five IR and five IS subjects, apoB100 kinetics were determined in the fasting state using a bolus dose of deuteroleucine and multicompartmental modeling. IR subjects had significantly lower fractional catabolic rates (FCR) in the larger VLDL1 (-70%), the smaller VLDL2 (-71%), and the IDL (-53%) fractions. No significant differences in production rates were observed for any lipoprotein class. There was a significant correlation between the sum of insulins and the FCR of the apoB100 of VLDL1 (rho = -0.65, P = 0.05) and of IDL (rho = -0.85, P = 0.004). The correlation coefficient of the sum of insulins and the FCR of VLDL2 was -0.61 with P = 0.067. We conclude that in this population of African American males, IR is correlated with a decreased FCR of apoB100 in VLDL and IDL and elevated plasma levels of apoB and triglycerides (TG). These changes might be explained by decreased clearance of the TG-rich lipoproteins. We postulate that this may reflect decreased lipoprotein and/or hepatic lipase activity related to insulin resistance and its association with obesity.
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PMID:A study of the metabolism of apolipoprotein B100 in relation to insulin resistance in African American males. 1046 Jun 97

The aim of this investigation was to determine the time course of changes in serum glucose, insulin and lipid levels, as well as lipid and protein content and lipolytic activities in insulin target organs (liver, adipose tissue and muscle), in macrosomic offspring of streptozotocin-induced mildly hyperglycaemic rats. Food intake and nutritional efficiency were also evaluated. Mild hyperglycaemia in pregnant rats was induced by intraperitoneal injection of streptozotocin (40 mg/kg body weight) on day 5 of gestation. Control pregnant rats were injected with citrate buffer. At birth, macrosomic pups (birth weight >1.7 S.D. greater than the mean value for the control pups) had higher serum insulin, glucose and lipid levels than control pups. These macrosomic rats maintained accelerated postnatal growth combined with high adipose tissue weight up to 12 weeks of age. These rats were not hyperphagic; however, they had higher food efficiency and fat storage capacity with higher adipocyte lipoprotein lipase activity, which contributed to persisting obesity. Hepatic lipase activity was increased in macrosomic rats at all ages. Moreover, macrosomia was associated with metabolic disturbances that varied according to age and sex. After 1 month, several alterations observed at birth had disappeared. Serum glucose, insulin and lipid levels in male and female macrosomic rats became similar to those of their respective controls. At 2 months of age, hepatic and serum triacylglycerol levels were higher in macrosomic females than in controls. By 3 months, macrosomic rats (both males and females) had developed insulin resistance with hyperinsulinaemia, hyperglycaemia, and higher serum and hepatic lipids. In conclusion, macrosomia was associated with alterations in glucose and lipid metabolism through to adulthood. It should be considered as an important potential risk factor for obesity and its metabolic complications.
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PMID:Time course of changes in serum glucose, insulin, lipids and tissue lipase activities in macrosomic offspring of rats with streptozotocin-induced diabetes. 1060 Jun 55

We investigated in a pilot study the effect of testosterone suppression on lipoprotein metabolism, insulin, and leptin in 10 men who were treated either with cetrorelix, an antagonist of gonadotropin releasing hormone, or with placebo (P). Group C + C (n = 4) was treated with 10 mg cetrorelix as daily subcutaneous injections for five days and with a subsequent injection of 60 mg cetrorelix depot. Group C + P (n = 3) received 10 mg cetrorelix as daily intramuscular injections for five days and a subsequent injection of placebo depot. Group P + P (n = 3) received placebo both as daily and depot injections. Treatment with cetrorelix reversibly suppressed testosterone to castrate levels for three weeks in group C + C and for one week in group C + P. Compared to baseline, treatment with cetrorelix increased serum levels of apolipoprotein (apo) A-I, HDL subclass LpA-I, insulin, and leptin. In the group P + P, treatment with placebo was not associated with any change of these parameters. Compared to baseline and group P + P, treatment with cetrorelix in groups C + C and C + P did not lead to considerable or consistent changes in the plasma activities of lecithin:cholesterol acyltransferase (LCAT), phospholipid transfer protein (PLTP), cholesteryl ester transfer protein (CETP), lipoprotein lipase, and hepatic lipase (HL). Only the pooled data of groups C + C and C + P unraveled small but statistically significant decreases of HL and CETP activities in response to cetrorelix. In conclusion, the small or absent effects of cetrorelix on LCAT, CETP, PLTP, LPL, and HL indicate that testosterone regulates HDL levels by other metabolic pathways. The increases of insulin and leptin in response to cetrorelix suggest that testosterone influences HDL metabolism also via obesity and insulin resistance. These effects, however, are rather in contrast to the HDL raising effect of suppressed testosterone.
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PMID:Effects of testosterone suppression in young men by the gonadotropin releasing hormone antagonist cetrorelix on plasma lipids, lipolytic enzymes, lipid transfer proteins, insulin, and leptin. 1061 83

Plasma phospholipid transfer protein (PLTP) is thought to play a major role in the facilitated transfer of phospholipids between lipoproteins and in the modulation of high density lipoprotein (HDL) particle size and composition. However, little has been reported concerning the relationships of PLTP with plasma lipoprotein parameters, lipolytic enzymes, body fat distribution, insulin, and glucose in normolipidemic individuals, particularly females. In the present study, 50 normolipidemic healthy premenopausal females were investigated. The relationships between the plasma PLTP activity and selected variables were assessed. PLTP activity was significantly and positively correlated with low density lipoprotein (LDL) cholesterol (r(s) = 0.53), apoB (r(s) = 0.44), glucose (r(s) = 0.40), HDL cholesterol (r(s) = 0.38), HDL(3) cholesterol (r(s) = 0.37), lipoprotein lipase activity (r(s) = 0.36), insulin (r(s) = 0.33), subcutaneous abdominal fat (r(s) = 0.36), intra-abdominal fat (r(s) = 0.29), and body mass index (r(s) = 0.29). HDL(2) cholesterol, triglyceride, and hepatic lipase were not significantly related to PLTP activity. As HDL(2) can be decreased by hepatic lipase and hepatic lipase is increased in obesity with increasing intra-abdominal fat, the participants were divided into sub-groups of non-obese (n = 35) and obese (n = 15) individuals and the correlation of PLTP with HDL(2) cholesterol was re-examined. In the non-obese subjects, HDL(2) cholesterol was found to be significantly and positively related to PLTP activity (r(s) = 0.44). Adjustment of the HDL(2) values for the effect of hepatic lipase activity resulted in a significant positive correlation between PLTP and HDL(2) (r(s) = 0.41), indicating that the strength of the relationship between PLTP activity and HDL(2) can be reduced by the opposing effect of hepatic lipase on HDL(2) concentrations. We conclude that PLTP-facilitated lipid transfer activity is related to HDL and LDL metabolism, as well as lipoprotein lipase activity, adiposity, and insulin resistance.
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PMID:PLTP activity in premenopausal women. Relationship with lipoprotein lipase, HDL, LDL, body fat, and insulin resistance. 1068 7

We examined the effect of genetic polymorphisms of proteins regulating intrahepatic processing of apolipoprotein B-100 (apoB) and the supply of neutral lipids to the liver on the hepatic secretion of very low density lipoprotein (VLDL) apoB in obesity. Hepatic secretion of very low density apolipoprotein B-100 (VLDL apoB) was measured using an infusion of [1-(13)C]leucine in 29 obese men. Isotopic enrichment and turnover of VLDL apoB was determined using gas chromatography-mass spectrometry and multi-compartmental modelling, respectively. Visceral fat was measured by magnetic resonance imaging. Genotypes for the apoB signal peptide (SP27/SP24 alleles), microsomal triglyceride transfer protein promoter (MTP, -493 G/T alleles), apoE (E2, E3, E4 alleles), hepatic lipase promoter (-514 C/T alleles), and cholesteryl ester transfer protein (CETP, Taq1B B1/B2 alleles) were determined using polymerase chain reaction. Statistically significant associations were found between hepatic secretion of apoB and allelic combinations of i) apoB SP with apoE (P = 0.02), hepatic lipase (P = 0.02), and CETP (P = 0. 006) genes, ii) MTP promoter with CETP genes (P = 0.03); the association with apoBSP/MTP promoter allelic combinations just failed to reach significance (P = 0.06), however. The CETP/apoBSP allelic combination was the most significant predictor of apoB secretion, and this was independent of visceral fat, plasma lathosterol and insulin levels, and dietary fat. SP24 carriers who were homozygous for CETP B1 had 60% lower apoB secretion than B2 heterozygotes who were non-carriers of SP24 (10.5 +/- 1.74 mg/kg fat free mass/day, n = 7 vs. 26.1 +/- 3.16, n = 22). The data suggest that variation in both the apoB and CETP genes may be a major genetic determinant of the hepatic secretion of apoB in men with visceral obesity.
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PMID:Genotypic associations of the hepatic secretion of VLDL apolipoprotein B-100 in obesity. 1070 96

Abdominal obesity is associated with numerous metabolic alterations, such as hypertriglyceridemia and low levels of high density lipoprotein (HDL) cholesterol. However, compared with abdominally obese white individuals, abdominally obese black individuals have been characterized by higher plasma HDL cholesterol levels, suggesting that the impact of abdominal fat accumulation on the lipoprotein-lipid profile may differ among ethnic groups. Therefore, we have compared the associations between body fatness, visceral adipose tissue (AT) accumulation, and metabolic risk variables in a sample of 247 white men and 240 white women versus a sample of 93 black men and 143 black women. Although no difference in mean total body fatness was found between the 2 race groups, white men had higher levels of visceral AT than did black men (P<0.001). Despite the fact that black women had a greater body fat content than did white women, black women had levels of visceral AT that were similar to those of white women, suggesting a lower susceptibility to visceral obesity in black women. This lower accumulation of visceral AT in blacks was accompanied by significantly reduced apolipoprotein B concentrations and ratios of total cholesterol to HDL cholesterol as well as higher plasma HDL cholesterol levels (P<0.05) compared with those values in whites. Irrespective of sex, higher postheparin plasma hepatic lipase (HL) and lower lipoprotein lipase (LPL) activities were found in whites, resulting in an HL/LPL ratio that was twice as high in whites as in blacks (P<0.005). Although differences in lipoprotein-lipid levels were noted between whites and blacks, results from multiple regression analyses revealed that after control for morphometric and metabolic variables of the study (body fat mass, visceral AT, LPL, HL, and age), ethnicity had, per se, only a minor contribution to the variance in plasma lipoprotein levels. Thus, our results suggest that the higher plasma HDL cholesterol levels and the generally more cardioprotective plasma lipoprotein profile found in abdominally obese black versus white individuals are explained, at least to a certain extent, by a lower visceral AT deposition and a higher plasma LPL activity in black individuals.
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PMID:Race, visceral adipose tissue, plasma lipids, and lipoprotein lipase activity in men and women: the Health, Risk Factors, Exercise Training, and Genetics (HERITAGE) family study. 1093 3

Cardiovascular risk factors as well as morbidity and mortality from coronary heart disease among Turkish adults are herein reviewed. Lipids and lipoproteins are in focus, but other relevant risk factors are also discussed. Turks have distinctively low levels of total and high-density lipoprotein (HDL)-cholesterol, associated with high levels of hepatic lipase and fasting triglycerides. In addition, physical inactivity is common in both genders; close to 60% of men have the smoking habit, while obesity is common among Turkish women leading to a high prevalence of hypertension and diabetes in them. These factors probably account for the unanticipated fact that Turkish adults have the pattern of causes of death similar to a developed population, although the process of industrialization is ongoing, the structure of its population is young and overall cholesterol levels are comparatively low. The age-standardized coronary heart disease death rate is estimated to rank among the highest in Europe. The leading independent predictors of coronary events and death [systolic blood pressure, total/HDL-cholesterol ratio, followed by diabetes and (central) obesity] are related to the metabolic syndrome, estimated to prevail in 3-4% of adults aged 30 or over, and to underlie one-eighth of cases of coronary disease. Since several adverse factors exhibit a rising trend, primary and secondary prevention of cardiovascular disease must assume a much higher priority in various issues in Turkey than it currently does.
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PMID:Risk factors and cardiovascular disease in Turkey. 1168 77

The socio-economic impact of obesity, one of the most prevalent medical disorders in Western society, is mainly due to its association with a higher risk of coronary heart disease. It is likely that atherosclerosis develops against a background of obesity as a result of the insulin resistance that is invariably present in overweight and obese subjects. Fasting plasma lipids may be normal in obese subjects, but they are usually affected by postprandial hyperlipidemia, which is probably due to competition between chylomicrons and VLDL for the same metabolic pathways. The basis for the impaired clearance of atherogenic chylomicron remnants is the fact that obesity causes hepatic apo B-VLDL overproduction, and thus leads to competition with chylomicrons and their remnants at the lipolytic pathway (lipoprotein lipase and hepatic lipase) and receptor level (LDL-receptor and remnant-receptor). The overproduction of VLDL is probably caused by an enhanced hepatic flux of free fatty acids in both the postprandial (from the lipolysis of triglyceride rich particles) and postabsorptive states (from adipocytes). Weight reduction by means of life-style changes, supported by medical interventions with inhibitors of intestinal fat absorption (e.g. Orlistat) or appetite suppressants (e.g. Sibutramine), is essential in order to decrease the risk of atherosclerosis. Furthermore, improvement of risk factors can be achieved by means of fibrate treatment to modulate fasting and postprandial triglyceride levels. Treatment with cholesterol synthesis inhibitors ("statins") may reduce hepatic VLDL production and increase the clearance of atherogenic remnants by upregulating LDL-receptors, thus leading to improved fasting lipid levels and enhanced clearance of chylomicron remnants. Finally, the use of thiazolidinedione derivatives to improve insulin sensitivity may be one of the options for reducing the risk of atherosclerosis in obese subjects.
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PMID:Obesity and free fatty acids: double trouble. 1143 90

Altered plasma levels of lipids and lipoproteins, obesity, hypertension, and diabetes are major risk factors for atherosclerotic cardiovascular disease. To identify genes that affect these traits and disorders, we looked for association between markers in candidate genes (apolipoprotein AII (apo AII), apolipoprotein AI-CIII-AIV gene cluster (apo AI-CIII-AIV), apolipoprotein E (apo E), cholesteryl ester transfer protein (CETP), cholesterol 7alpha-hydroxylase (CYP7a), hepatic lipase (HL), and microsomal triglyceride transfer protein (MTP)) and known risk factors (triglycerides (Tg), total cholesterol (TC), apolipoprotein AI (apo AI), apolipoprotein AII (apo AII), apolipoprotein B (apo B), body mass index (BMI), blood pressure (BP), leptin, and fasting blood sugar (FBS) levels.) A total of 1,102 individuals from the Pacific island of Kosrae were genotyped for the following markers: Apo AII/MspI, Apo CIII/SstI, Apo AI/XmnI, Apo E/HhaI, CETP/TaqIB, CYP7a/BsaI, HL/DraI, and MTP/HhpI. After testing for population stratification, family-based association analysis was carried out. Novel associations found were: 1) the apo AII/MspI with apo AI and BP levels, 2) the CYP7a/BsaI with apo AI and BMI levels. We also confirmed the following associations: 1) the apo AII/MspI with Tg level; 2) the apo CIII/SstI with Tg, TC, and apo B levels; 3) the Apo E/HhaI E2, E3, and E4 alleles with TC, apo AI, and apo B levels; and 4) the CETP/TaqIB with apo AI level. We further confirmed the connection between the apo AII gene and Tg level by a nonparametric linkage analysis. We therefore conclude that many of these candidate genes may play a significant role in susceptibility to heart disease.
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PMID:Candidate genes involved in cardiovascular risk factors by a family-based association study on the island of Kosrae, Federated States of Micronesia. 1211 31


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