离子碘和分子碘过量对甲状腺功能与形态影响

目的　比较离子碘和分子碘过量对非碘缺乏Wistar大鼠甲状腺功能和形态的影响及差别。方法　固相免疫放射分析法测定实验大鼠血清TSH ,放射免疫分析法测定血清TT4 、TT3 。砷铈分光光度法测定尿碘。光、电镜下观察甲状腺内形态学变化 ,用图像分析仪测量滤泡上皮细胞高度和滤泡腔面积。结果　补充 840 μg碘 /L 90d时 ,可使血清TSH值增高 ,但是未见显著性差异。血清TT4 明显高于双蒸馏水 (DDW )组 ,P <0 0 5,但同剂量离子碘和分子碘比较 ,血清TT4 值无显著性差异。补碘组光、电镜下可见滤泡腔面积增大 ,滤泡上皮细胞变扁 ,细胞核染色深 ,滤泡融合破裂 ,巨滤泡形成 ,毛细血管减少。超微结构显示甲状腺滤泡上皮细胞内质网扩张 ,次级溶酶体增多 ,微绒毛减少 ,染色体浓集。与DDW组相比 ,滤泡上皮细胞高度明显降低 ,滤泡腔面积增大 ,P均 <0 0 5。相同剂量离子碘和分子碘比较无显著性差异。结论　碘摄入浓度 >840 μg/L时 ,会对大多部分甲状腺滤泡上皮细胞产生抑制和破坏 ,使血清TT4 值明显增高 ,离子碘和分子碘对甲状腺影响无明显区别     

Adapted changes in left ventricular structure and function in severe uncomplicated obesity

OBJECTIVE: A massive amount of fat tissue, as that observed in obese subjects with BMI over 50 kg/m(2), could affect cardiac morphology and performance, but few data on this issue are available. We sought to evaluate cardiac structure and function in uncomplicated severely obese subjects. RESEARCH METHODS AND PROCEDURES: We studied 55 uncomplicated severely obese patients, 40 women, 15 men, mean age 35.5 +/- 10.2 years, BMI 51.2 +/- 8.8 kg/m(2), range 43 to 81 kg/m(2), with a history of fat excess of at least 10 years, and 55 age-matched normal-weight subjects (40 women, 15 men, mean BMI 23.8 +/- 1.2 kg/m(2)) as a control group. Each subject underwent an echocardiogram to evaluate left ventricular (LV) mass and geometry and systolic and diastolic function. RESULTS: Severely obese subjects showed greater LV mass and indexed LV mass than normal-weight subjects (p < 0.01 for all parameters). Nevertheless, LV mass was appropriate for sex, height(2.7), and stroke work in most (77%) uncomplicated severely obese subjects. In addition, no significant difference in LV mass indices and LV mass appropriateness between obese subjects with BMI > or = 50 kg/m(2) and those with BMI < or = 50 kg/m(2) was found. Obese subjects also showed higher ejection fraction and midwall shortening than normal-weight subjects (p = 0.05 and p < 0.01, respectively), suggesting a hyperdynamic systolic function. No significant difference in systolic performance between obese subjects with BMI > or = 50 kg/m(2) and those with BMI < or = 50 kg/m(2) was seen. DISCUSSION: Our data show that uncomplicated severe obesity, despite the massive fat tissue amount, is associated largely with adapted and appropriate changes in cardiac structure and function.     

Influence of obesity on immune function

OBJECTIVE: To compare immune function in obese and nonobese subjects. DESIGN: Obese and nonobese subjects were compared cross-sectionally. To test for the influence of other factors on immunity, aerobic fitness, psychological well-being, and serum levels of glucose, triglycerides, and cholesterol were measured and included in multiple regression models to determine their comparative effects. SUBJECTS/SETTING: Community-based subjects included 116 obese women (age = 44.3 +/- 9.7 years, body mass index = 33.2 +/- 6.5) and 41 nonobese women (age = 42.2 +/- 10.9 years, body mass index = 21.2 +/- 1.9). STATISTICAL ANALYSES PERFORMED: Independent t tests, Pearson product moment correlations, and stepwise multiple regression procedures. RESULTS: Obesity was linked to elevated leukocyte and lymphocyte subset counts (except for natural killer and cytotoxic/suppressor T cells), suppressed mitogen-induced lymphocyte proliferation (an index of T- and B-cell function), higher monocyte and granulocyte phagocytosis and oxidative burst activity, and normal activity of natural killer cells. APPLICATIONS/CONCLUSIONS: These data support the contention that obesity is associated with alterations in immune function. Further research is needed to link immunosuppression with the previously reported elevated risk of infection among the obese.     

超重及肥胖儿童胰岛素敏感性及β细胞功能研究

【目的】研究超重及肥胖儿童胰岛素敏感性、胰岛素抵抗及β细胞功能。【方法】随机抽取新疆乌鲁木齐市天山区六所中小学10～15岁的在校学生527人,根据体重指数(bodymassindex,BMI)分为超重肥胖组和正常对照组,并进行体格检查和实验室生化检测。采用HOMA-IR,HOMA-B及胰岛素敏感指数(insulinsensitiveindex,ISI)评价。【结果】超重及肥胖组的ISI显著低于正常组(P<0.01),胰岛素抵抗指数(insulinresisindex,IR)、β细胞功能指数(β-cellfunctionindex,HBCI)显著高于正常组(P<0.01)。同时ISI与BMI负相关,IR与BMI、WHR呈正相关,HBCI与BMI呈正相关,与WHI呈负相关。【结论】超重肥胖儿童存在胰岛素的敏感降低、胰岛素抵抗及β细胞功能异常。     

超重肥胖对8~9岁儿童心脏结构和功能的影响

评价超重、肥胖儿童心脏结构和功能情况,旨在评估心脏早期改变的风险性和不良后果,为加强早期干预和预防成年心血管疾病提供参考.方法 选取北京市海淀区昌平区5所小学的1 034名8~9岁儿童(男514名,女520名),依照BMI分类标准,男、女各分成体重正常组、超重组和肥胖组.对所有受试者进行超声心动图检查,并分性别比较心脏结构和功能指标.结果 与体重正常组儿童相比,肥胖男童主动脉根部内径(AOD)、舒张末期室间隔厚度(IVSd)、左心室舒张末期内径(LVIDd)、舒张末期左室后壁厚度(LVPWd)、左心室舒张末期容积(EDV)、左心室质量(LVM)、每搏量(SV)、心输出量(CO)、左心室质量指数(LVMI)分别增加了6.7%,13.4%,7.6%,15.3%,19.7%,34.6%,18.3%,23.7%,8.8%(P值均<0.01);肥胖女童AOD,IVSd,LVIDd,LVPWd,EDV,LVM,LVMI,SV,CO分别增加了4.9%,9.1%,9.1%,12.1%,22.7%,32.9%,7.3%,22.5%,26.0%(P值均<0.01).超重儿童ADD,LVIDd,IVSd,LVPWd,EDV,LVM,SV,CO均高于体重正常儿童(P值均<0.05).不同BMI儿童射血分数(EF),短轴缩短率(FS)差异均无统计学意义.男童BMI与AOD,IVSd,LVIDd,LVPWd,RWT,EDV,LVM,LVMI,HR,CO,SV呈正相关(r值分别为0.217,0.289,0.288,0.338,0.156,0.291,0.534,0.227,0.173,0.322,0.262,P值均<0.01);女童BMI与IVSd,LVIDd,LVPWd,EDV,LVM,LVMI,CO,SV呈正相关(r值分别为0.146,0.322,0.224,0.329,0.444,0.158,0.288,0.287,P值均<0.01).结论 8~9岁超重儿童即可出现左心室扩大、室壁增厚、左室质量增加、心脏功能异常,并随超重向肥胖过渡而加重,且BMI对男童心脏结构和功能影响更大.     

重度子痫前期心脏形态及功能的研究

目的:探讨重度子痫前期患者心脏形态及功能的变化。方法:早发型重度子痫前期46例,晚发型重度子痫前期62例,正常妊娠86例,比较彩色多普勒心脏超声结果中各指标的差异来评估心脏形态及功能的变化。结果:与正常妊娠组相比,晚发型重度子痫前期组左心各径线明显增大,差异有统计学意义(P<0.05);收缩期指标差异无统计学意义(P>0.05),但4例LVEF<55%;舒张期指标显著降低,差异有统计学意义(P<0.01);心包积液发生率显著增高,差异有统计学意义(P<0.05)。早发型重度子痫前期比晚发型左房增大更显著,差异有统计学意义(P<0.01)。结论:重度子痫前期患者心脏形态改变以左房室腔增大、室壁及室间隔增厚、心包积液为主,伴左室舒张功能的损害,个别病例收缩功能轻度受损。早发型重度子痫前期心血管损害程度超过晚发型。     

不同脂肪乳剂对阻塞性黄疸大鼠肝脏功能和形态学的影响

目的：比较不同脂肪酸来源的全胃肠外营养（TPN）对胆总管结扎大鼠肝脏功能和形态学的影响。观察不同脂肪酸对阻塞性黄疸大鼠受损肝脏的作用,为临床阻塞性黄疸患应用TPN提供实验依据。方法：采用SD大鼠36只,随机分4组,每组9只,其中A组为假手术＋经口饮食对照组;余3组均行胆总管结扎术：B组为经口饮食对照组,C,D组分别给予以长链（LCT）或中长链脂肪酸（MCT／LCT）为脂肪来源的TPN。结果：应用长链脂肪酸大鼠的血清AKP,g-GT,血清总胆红素,直接胆红素和胆汁酸水平均高于应用中长链脂肪酸大鼠。对实验大鼠肝脏形态学观察发现,应用LCT的大鼠肝细胞损害较经口饮食对照大鼠有所加重,而应用MCT／LCT的大鼠肝细胞损害未见加重。结论：短期应用合理糖脂比,热氮比和合适脂肪来源的TPN并不加重阻塞性黄疸大鼠的肝脏损害和胆红素代谢紊乱。     

Television watching, videogames, and excess of body fat in Spanish adolescents: the AVENA study

OBJECTIVE: We assessed the individual association of sedentary behaviors with the risk of overweight and excess body fat (overfat) in adolescents. METHODS: A representative sample (1960 subjects, 1012 males, age 13-18.5 y) of Spanish adolescents was studied within the framework of the Alimentación y Valoración del Estado Nutricional de los Adolescentes (AVENA) study. Television (TV) watching, videogame and computer usage, doing homework, and the way students got to school, physical activity, and socioeconomic status were analyzed. Anthropometrics were measured to describe overweight (International Obesity Task Force cutoffs for body mass index) and overfat (body fat percentage >85th percentile). RESULTS: When all subjects were considered as an entire group, the overweight risk increased by 15.8% (P < 0.05) per increasing hour of TV watching. The overweight risks decreased by 32.5% in females, 22% per increasing year of age, and 12.5% by increasing socioeconomic status by 1 U (all Ps < 0.05). The obesity risks decreased with age by 17.8% per year in males and 27.1% in females (both Ps < 0.05). The overfat risks increased by 26.8% and 9.4% per increasing hour of TV and weekend videogame usage, respectively (both Ps < 0.05). In males, the overfat risk increased by 21.5% per increasing hour in weekend videogame usage (P < 0.05). Each hour of TV use increased the overfat risks by 22% in males and 28.3% in females (both Ps < 0.05). CONCLUSIONS: Time spent watching TV increased the risk of overweight and obesity in Spanish adolescents, but the effect was influenced by age, sex, and socioeconomic status. Moreover, an excess of body fat was more directly explained by the time spent watching TV and playing videogames during the weekend.     

三氯生改善高脂饮食诱导小鼠肥胖的实验研究

目的 探究三氯生对高脂饮食诱导小鼠肥胖的改善作用及可能机制。方法 选取8周龄雄性C57BL/6J小鼠,随机分为空白对照组和高脂饲料组,分别给予普通饲料和高脂饲料。12周后将高脂饲料组随机分为模型组和低、中、高剂量三氯生组,每日分别灌胃100、200、400 mg/(kg·d）剂量的三氯生,模型组以等体积溶剂灌胃,期间记录摄食量及体重。8周后处死小鼠,收集腹股沟皮下脂肪、附睾脂肪、肝脏和全血。HE染色观察脂肪细胞和肝细胞形态;检测血清中甘油三酯（TG）、总胆固醇（TC）、谷丙转氨酶（ALT）和谷草转氨酶（AST）及白蛋白（ALB）含量;检测小鼠肝脏脂合成基因Fasn、Srebp-1c,以及脂肪氧化基因Pparα、Cpt1的表达情况。结果 各三氯生组与模型组小鼠摄食量无显著差异。灌胃8周后,低、中、高剂量三氯生组体重和脂体比均低于模型组,血清TG、TC、ALT和AST水平下降;HE染色可见脂肪细胞缩小,肝细胞内脂滴空泡减少,各组小鼠血清ALB含量无显著差异。相比于模型组,各三氯生组脂肪酸合成调控分子Fasn和Srebp-1c的m RNA与蛋白水平下降,而脂肪酸氧化基因Pparα和Cpt1的...     

Prevalence of uncomplicated obesity in an Italian obese population

OBJECTIVE: The existence of healthy obese subjects has been suggested but not clearly reported. We sought to address the prevalence of uncomplicated obesity and adverse risk factors in a large Italian obese population. RESEARCH METHODS AND PROCEDURES: This was a cross-sectional study of a population of consecutive Italian obese subjects. We studied 681 obese subjects (514 women and 167 men), with a mean age of 41.1+/-13.9 years (range, 16 to 77 years), mean BMI of 40.2+/-7.6 kg/m2 (range, 30 to 89.8 kg/m2), and a history of obesity for 20.5+/-7 years (range, 10.5 to 30 years). Anthropometric, metabolic, cardiac, and obesity-related risk factors were evaluated. RESULTS: The prevalence of uncomplicated subjects was 27.5%, independent of BMI and duration of obesity. The youngest group of obese subjects showed a higher, but not statistically significantly higher, prevalence of uncomplicated obesity. No statistical difference for the prevalence of impaired fasting glucose, glucose intolerance, high triglycerides, high total cholesterol, low-density lipoprotein cholesterol, and high-density lipoprotein cholesterol among BMI categories (from mild to extremely severe obesity degree) was found. Obese subjects with BMI>50 kg/m2 showed a higher prevalence of high blood pressure only when they were compared with the group with a BMI of 30 to 35 kg/m2 (p<0.01). Obese subjects with BMI>40 kg/m2 showed a higher prevalence of hyperinsulinemia than subjects with BMI 30 to 35 kg/m2 (p<0.01). DISCUSSION: This study shows that a substantial part of an Italian obese population has uncomplicated obesity, and the prevalence of adverse risk factors in this sample is unexpectedly low and partially independent of obesity degree. Uncomplicated obesity could represent a well-defined clinical entity.     

Influence of intravenous hyperalimentation on cardiac dimensions and heart function

Eleven severe malnourished patients, mean age 34 yrs and mean weight 66 per cent of ideal body weight, were studied to evaluate the effect of intravenous hyperalimentation on the function and size of the heart. Left ventricular size and systolic function were measured before and after a mean weight gain of 19 per cent with electro, vector, echo and phonomechanographic methods. During hyperalimentation a statistically significant increase in left ventricular mass (p<0.01) was observed. Correction for body weight showed a parallel increase between the parameters and weight gain. Echocardiographic and phonomechanographic indexes of left ventricular systolic function remained unchanged. A decrease of the amplitude of the maximal spatial QRS vector was shown by vectocardiography. These results indicate that during intravenous hyperalimentation of the severe malnourished a proportional increase in cardiac size and mass occurs with preservation of the left ventricular systolic function.     

Relationship of insulin sensitivity and left ventricular mass in uncomplicated obesity

OBJECTIVE: We studied uncomplicated obesity as a model to evaluate the influence of insulin sensitivity per se on left ventricular mass (LVM) and geometry. RESEARCH METHODS AND PROCEDURES: We selected 50 obese subjects (BMI > 30 kg/m(2); 38 women and 12 men; mean age, 38.4 +/- 10 years; BMI, 36.4 +/- 10.5 kg/m(2)) with normal blood pressure, glucose tolerance, and plasmatic lipid levels. Thirty lean subjects formed the control group. Each subject underwent euglycemic insulin clamp (7 pmol/min per kg) to evaluate whole body glucose use (M index) and echocardiogram to calculate LVM and indexed LVM. RESULTS: Insulin-resistant obese subjects had higher LVM, LVM/h(2.7), LVM/body surface area, and LVM/fat-free mass(kg) (p = 0.001; p = <0.001 p = 0.001, and p = 0.04, respectively) than obese subjects with normal insulin sensitivity. Multivariate regression analysis showed that M index was the strongest independent correlate of LVM (r(2) = 0.34; p = 0.03). DISCUSSION: Our findings showed that insulin resistance, in uncomplicated obesity, is associated with an increased LVM and precocious changes of left ventricular geometry, whereas preserved insulin sensitivity is not associated with increased LVM.     

Weight cycling is associated with body weight excess and abdominal fat accumulation: A cross-sectional study

Background & aims

To investigate the association between history of multiple weight loss diets followed by weight regain, namely weight cycling (WCy), and both body weight excess and abdominal fat accumulation.

Methods

A one-day cross-sectional survey (“Obesity-Day”) including 914 participants (605F:309M). Anthropometric variables (body mass index [BMI], waist circumference [WC] and waist-to-height ratio [WtHR]), covariates and WCy (≥5 intentional weight loss episodes of ≥5 kg followed by rapid return to pre-diet or higher body weight) were assessed by a self-administered questionnaire, interview and physical examination.

Results

Data on central fat accumulation (by WC and WtHR) were available in a representative sub-group (n = 600). WCy was reported by 119 participants (13.0%) of total population and by 79 (13.2%) of those with available data on central fat accumulation. At multivariable linear regressions WCy was independently associated with higher BMI (P = .004), WC (P = .011) and WtHR (P = .008). Sensitivity analyses, performed after excluding those being on a diet at the time of assessment, confirmed these findings.

Conclusions

A history of WCy appears related to body weight excess and abdominal fat accumulation. These findings support the importance of designing adequate weight loss programs to achieve long-term weight maintenance and to prevent undesirable and unhealthy weight accumulation.     

Dietary fat:carbohydrate ratio and obesity in middle-aged men

Nutrient intakes from 7-d diet records were compared with hydrostatically determined body composition in 155 sedentary obese men aged 30-59 y. Percent body fats ranged from 18.6 to 40.3. The men ate (mean +/- SD) 2570 +/- 514 kcal/d: 15.6 +/- 2.6% from protein, 40.7 +/- 5.7% from fat, 37.5 +/- 6.9% from carbohydrate, and 6.2 +/- 6.0% from alcohol. Percent body fat correlated positively (p less than 0.05) with g/1000 kcal intake of total, saturated, and monounsaturated fatty acids and negatively with carbohydrates and plant protein. Total calories, number of meals, and distribution of calories were unrelated to percent body fat, total weight, or fat-free mass. The higher proportion of fat and carbohydrate in the diet may contribute to obesity in men. The modest caloric intake of these men and the lack of correlation between percent body fat and total calories suggest that calorie differences are not the major cause of the variations in obesity in these men.     

甲状腺素减少对新生儿心功能及心电生理的影响

目的 探讨先天性甲状腺功能减少症(甲低)对新生儿左右心功能以及心电生理的影响.方法 对50例确诊为甲低的足月新生儿行超声心动图检查及心电图检查,并与35例对照组新生儿进行比较.分别用传统M型超声心动图、脉冲多普勒(PWD)及组织多普勒超声心动图(TDE)检测各组新生儿的左心和右心收缩舒张功能,分别测量左室射血分数(LVEF)、左室短轴缩短率(LVFS)、左房径(LA)、主动脉径(AO),计算LA/AO,二尖瓣口及三尖瓣口舒张早期充盈峰值速度(E),舒张晚期充盈峰值速度(A),计算E/A值,二尖瓣环和三尖瓣环收缩期运动峰值速度(Sa)、舒张早期运动峰值速度(Ea)、舒张晚期运动峰值速度(Aa),计算Ea/Aa值.同时进行常规十二导联心电图检查(ECG),分别检测心率(HR)、PR间期(PR)、QT间期(QT)、QRS波电轴(QRSa)、QRS波时限(QRS)、校正QT间期(QTC)等指标.结果 传统M型心超显示LA、AO及LA/AO在甲低组与对照组间无显著性差异,甲低组LVEF和LVFS显著低于对照组;PWD显示甲低组二尖瓣与三尖瓣口血流E峰及E/A值均低于对照组,但A峰无显著性差异.QTVI示甲低组二尖瓣及三尖瓣环Sa、Ea和Ea/Aa值均显著低于对照组,但Aa无显著性差异.甲低组HR显著低于对照组,PR间期及QT间期较对照组显著延长,但两组间QRS波电轴、QRS波时限及QTC差异无显著性意义.结论 先天性甲状腺功能减少症对新生儿可同时造成左心与右心的收缩、舒张功能损害,并对新生儿的窦房结起搏产生显著影响,引起心脏自律性改变,而心肌动作电位、房室传导等电生理活动则尚未受影响.     

Relationship of obesity to diabetes: influence of obesity level and body fat distribution

The relationship of clinical diabetes to body fat distribution and obesity level was examined in 15,532 women. After adjusting for relative weight, all upper body segment girth measurements (neck, bust, and waist) had strong positive associations with diabetes. In contrast, the lower body segment girth measurement (hips) had an equally strong but inverse association with diabetes. Based upon waist-to-hip girth ratio, women were divided into four subgroups. The prevalence of diabetes increased with increasing values of this ratio. Women in the upper quartile had about three times the prevalence of diabetes as women of comparable obesity level in the lowest quartile. Women with both upper body fat predominance and severe obesity had a relative risk of diabetes 10.3 times as great as nonobese subjects with lower body fat predominance. The results suggest that localization of fat in the upper body segment and severe obesity are two distinct additive risks for diabetes.     

The consequences of obesity and excess weight gain in pregnancy

The prevalence of obesity in pregnancy is rising exponentially; about 15-20% of pregnant women now enter pregnancy with a BMI which would define them as obese. This paper provides a review of the strong links between obesity and adverse pregnancy outcome which operate across a range of pregnancy complications. For example, obesity is associated with an increased risk of maternal mortality, gestational diabetes mellitus, thromboembolism, pre-eclampsia and postpartum haemorrhage. Obesity also complicates operative delivery; it makes operative delivery more difficult, increases complications and paradoxically increases the need for operative delivery. The risk of the majority of these complications is amplified by excess weight gain in pregnancy and increases in proportion to the degree of obesity, for example, women with extreme obesity have OR of 7·89 for gestational diabetes and 3·84 for postpartum haemorrhage compared to their lean counterparts. The consequences of maternal obesity do not stop once the baby is born. Maternal obesity programmes a variety of long-term adverse outcomes, including obesity in the offspring at adulthood. Such an effect is mediated at least in part via high birthweight; a recent study has suggested that the odds of adult obesity are two-fold greater in babies weighing more than 4 kg at birth. The mechanism by which obesity causes adverse pregnancy outcome is uncertain. This paper reviews the emerging evidence that hyperglycaemia and insulin resistance may both play a role: the links between hyperglycaemia in pregnancy and both increased birthweight and insulin resistance have been demonstrated in two large studies. Lastly, we discuss the nature and rationale for possible intervention strategies in obese pregnant women.     

A Meta-analysis of excess cardiac mortality on Monday

Background: Available evidence suggests a peak in the incidence of cardiovascular events on Mondays compared to other days of the week. The exact magnitude of the excess risk and the role of age and gender, however, remain unclear. Objective: To quantify the excess risk associated with the Monday peak in cardiovascular mortality and to explore the role of age and gender. Methods: A meta-analysis of available published studies reporting on weekly patterns in incidence of myocardial infarction and sudden cardiac death was performed. Results: Reports based on routinely collected data from population statistics (n &frac; 5) generally reported a lower odds ratio (OR) of an event on Monday than studies with a confirmed diagnosis (n &frac; 16). The pooled OR estimate based on population statistics was 1.04 (95%CI: 1.03; 1.05), whereas the pooled OR estimate based on confirmed diagnoses was 1.19 (95%CI: 1.17; 1.21). Subgroup analysis yielded an OR of 1.19 (95%CI: 1.07; 1.31) for men and 1.15 (95%CI: 0.99; 1.32) for women. Odds ratios for patients younger than 65 years of age and 65 or older were 1.22 (95%CI: 1.09; 1.36) and 1.16 (95%CI: 1.07; 1.27), respectively. The differences between subgroup odds ratios were not statistically significant. Conclusion: The incidence of sudden cardiac death is markedly increased on Monday, similar for men and women, and for subjects below and above 65 years of age.This revised version was published online in July 2005 with a correction in the title.     

Protein metabolism in obesity: effects of body fat distribution and hyperinsulinemia on leucine turnover

To examine whether moderate obesity and differences in body fat distribution are associated with abnormalities of protein metabolism, leucine turnover was measured in three groups of age-matched premenopausal women. Ten upper-body-obese (UB Ob), 10 lower-body-obese (LB Ob), and 10 nonobese (Non Ob) women were studied in an overnight postabsorptive condition (basal) and again during an infusion of low physiologic amounts of insulin (insulin clamp). Results showed that basal leucine carbon flux was greater (P less than 0.05) in UB Ob and LB Ob women than in Non Ob women (2.96 +/- 0.08 vs 3.14 +/- 0.16 vs 2.68 +/- 0.08 mumol.kg lean body mass-1.min-1, respectively; mean +/- SEM). Leucine carbon flux was not suppressed during the insulin-clamp study in UB Ob women but was in the LB Ob and Non Ob women. We conclude that moderate obesity is associated with increased proteolysis and that insulin's antiproteolytic actions are impaired in upper-body obesity. These findings could have implications for future studies of and treatment of obesity.