Human khat (Catha edulis) chewers have elevated plasma leptin and nonesterified fatty acids

In this study, the effect of regular khat (Catha edulis Forsk) chewing (200 and 400 g) in humans on plasma leptin, nonesterified fatty acid, triacyglycerol, and total cholesterol levels was investigated. The results presented show that khat chewing increases plasma leptin concentration particularly in individuals who chew 400 g of khat leaves. The significance of increased plasma leptin is in explaining the underlying mechanism of the observed effects associated with khat chewing such as loss of appetite, decreased body weight, and hyperthermia. The decreased body weight was evident from the significantly lower body mass index of the khat leaves chewers group as compared to the non–khat leaves chewers group (control). Moreover, like leptin, the plasma levels of nonesterified fatty acids were significantly higher in those chewing 400 g of khat leaves. On the other hand, the plasma levels of triacylglycerol were significantly lower in the 2 khat-chewers groups (200 and 400 g of khat leaves), whereas plasma cholesterol levels were not affected by the 2 levels of khat leaves used in this study. The significance of these results may suggest that khat leaves may contain a component(s) that has the ability to reduce body weight via decreasing appetite.     

瘦蛋白的分子生物学特性研究进展

瘦蛋白 (leptin)是由肥胖基因编码、脂肪细胞分泌的一种分子量为 16kDa的蛋白质 ,是一种重要的代谢调节信号 ,对人和动物的采食量、能量代谢、繁殖性能等具有重要调节功能 ,对人肥胖病的治疗和改善动物的生产性能、胴体组成等有良好的潜在应用前景 .主要概述了瘦蛋白基因的克隆、转录、表达调控以及瘦蛋白受体与信号转导等分子生物学特性     

甲状腺病变患者血清Leptin的浓度变化

目的探讨甲状腺病变患者血清瘦素(leptin)浓度的变化及意义.方法本文用放射免疫分析(RIA)方法测定了114例甲状腺病变患者血清Leptin和总睾酮(TT)的浓度.结果统计学处理结果显示各病变组男性与正常对照组男性间,Leptin和TT的浓度差异均有显著性意义.结论血清Leptin的浓度变化可作为了解甲状腺病变患者营养状况的辅助指标.     

Diurnal rhythms of leptin and ghrelin in the systemic circulation and in the gastric mucosa are related to food intake in rats

We investigated diurnal changes in leptin and ghrelin levels in the stomach and in the systemic circulation and their relation to food intake rhythms in Wistar rats housed at 22 °C with a 12-h light/dark cycle and free access to food and water. Animals were sacrificed every 3 h over a 24-h period. Leptin and ghrelin levels in serum and in the gastric mucosa were analysed by immunoassay. Leptin mRNA levels were determined in the gastric mucosa by RT-PCR and in different adipose tissue depots (epididymal, retroperitoneal and mesenteric) by Northern blot. Ghrelin mRNA levels were determined by Northern blot. Gastric and serum leptin levels displayed similar diurnal rhythms, rising during the dark phase and decreasing gradually during the light phase. Leptin expression in the different adipose tissue depots correlated positively with circulating leptin levels (P<0.05), although there were some depot-associated differences. Leptin mRNA levels in the mesenteric depot correlated positively with food intake (P<0.05). In blood, ghrelin levels rose sharply just before the onset of the dark phase and dropped suddenly just after. In the stomach, ghrelin levels were high during the fasting period of light and low during the night, and correlated inversely with food intake, gastric contents and serum leptin levels (P<0.05). Leptin and ghrelin in the stomach and in the systemic circulation thus show diurnal variations that are influenced by food intake rhythms. The results agree with a role for ghrelin as a stimulant of meal initiation.     

妊娠期糖尿病与瘦素水平变化的临床研究

目的　探讨瘦素水平与妊娠期糖尿病 (GDM)发病关系以及对其胎儿生长发育的影响。方法　采用放射免疫法测定GDM孕妇 2 0例 ,糖耐量减低 (IGT)孕妇 2 2例 ,正常孕妇 2 5例血清及其新生儿脐血的瘦素水平 ,同时测定这三组孕妇的胰岛素、C肽水平 ,并测量孕前体重指数和孕期体重增加指数 ,分析其与瘦素之间的关系。结果　GDM孕妇血清瘦素、胰岛素和C肽水平明显高于IGT组及正常组 (P <0 .0 0 1)。脐血瘦素水平与胎儿体重呈正相关 (P <0 .0 5 ) 。孕妇血清瘦素水平与胎儿体重无相关。孕妇血清瘦素水平与脐血瘦素水平无相关。GDM孕妇血清瘦素与孕前体重指数明显相关 (P <0 .0 5 ) ,与孕期体重增加指数无相关。结论　 (1)GDM孕妇血清瘦素水平明显高于正常孕妇 ,故瘦素可作为监控GDM的指标之一。(2 )GDM孕妇瘦素水平与脐血瘦素水平虽然不相关 ,提示胎儿瘦素是自身产生 ,但母亲糖尿病也可以影响胎儿产生更多的瘦素。     

A role for glucose and insulin preprandial profiles to differentiate meals and snacks

A physiological distinction between eating occasions may help account for contradictory findings on the role of eating frequency in energy homeostasis. We assessed this issue using a midafternoon eating occasion known in France as the goûter that often consists of snack foods. Among the 24 male subjects, 8 habitually consumed four meals per day, i.e., were usual goûter eaters (GE) and 16 habitually took 3 meals per day, i.e., usual non-goûter non-snack eaters (NGNSE). All subjects were time blinded from lunchtime and had to request subsequent meals. Blood was continuously withdrawn and collected with a change of tube every 10 min until dinner request. During the session, 8 of the non-goûter eaters (NGE) were offered a snack 210 min after lunch and were designated as non-goûter snack eaters (NGSE) if they ate. Results showed that the goûter was preceded by high hunger scores and a linear decline in plasma glucose (−9.0±3.0%, P<.05) and insulin concentrations (−22.9±6.0%, P<.05). These profiles were not observed before the snack. The dinner of GE was requested later and was smaller compared to NGNSE, whereas the snack altered neither time of request nor energy intake (EI) at dinner. Among blood variables, leptin at the onset of eating was the only factor that was predictive of both intermeal interval and EI. The glucose and insulin profiles indicate that snacks should not be considered as meals in studies on the role of eating frequency in energy homeostasis.     

1型糖尿病及肥胖儿童血清瘦素水平及与其它常用指标相关性分析

目的比较1型糖尿病及肥胖儿童血清瘦素水平。方法以EL1SA方法测定35例1型糖尿病、32例肥胖及35例健康儿童的血清瘦素水平。35例1型糖尿病患者中 ,7例为新患糖尿病伴酮症酸中毒的患者。通过测定C -肽水平来评估胰岛素的分泌。C -肽、血糖、糖化血红蛋白按常规方法测定。结果糖尿病患者血清瘦素水平低于对照组 (P<0.001)。肥胖儿童血清瘦素及C -肽水平高于糖尿病组及对照组。在糖尿病新患者中 ,经1个月的胰岛素治疗后 ,血清瘦素水平未有任何变化 (P>0.05)。在联合组中 ,瘦素与体重指数 (bodymassindex,BMI)及C -肽呈正相关(P<0.001) ,而与血糖及糖化血红蛋白呈负相关(P<0.05)。结论1型糖尿病患儿血清瘦素水平低可能与代谢控制有关的慢性胰岛素缺乏引起的。瘦素及胰岛素在保持身体体重稳定的过程中可能起着补充作用。     

Effects of a single bout of short-duration high-intensity and long-duration low-intensity exercise on insulin resistance and adiponectin/leptin ratio

ObjectivesModerate-intensity exercise improves insulin sensitivity, which may depend on the intensity, duration, and frequency of exercise. We examined the effects of a single bout of short-duration high-intensity exercise (HIE) and long-duration lowintensity exercise (LIE) on insulin sensitivity and the adiponectin/leptin ratio in individuals with different body mass indices (BMIs) who do not exercise regularly.MethodsWe enrolled 42 healthy volunteers aged 20–64 years and divided them into two groups based on BMI: BMI <24 kg/m² and BMI ≥27 kg/m². They were randomly assigned to either the short-duration (20 min) HIE (70%–80% heart rate reserve, HRR) or long-duration (60 min) LIE training groups (30%–40% HRR). Glucose, insulin, adiponectin, and leptin levels were assessed before training and at 0, 30, 60, and 120 min after training.ResultsWe finally analyzed 27 normal weight and 9 obese individuals. No significant differences were observed in the baseline information of both BMI groups. Homeostatic model assessment for insulin resistance significantly improved for both exercise patterns in the normal weight group and for the HIE pattern in the obese group (P < 0.01), whereas the adiponectin/leptin ratio increased significantly only among normal weight participants with the LIE intervention.ConclusionBoth exercise patterns in BMI <24 kg/m² and BMI ≥27 kg/m² benefit on insulin resistance. Therefore, people can choose the way they can fit to improve insulin resistance both short-duration high-intensity exercise and long-duration low-intensity exercise.     

单纯性肥胖症瘦素水平的临床意义

目的 :探讨单纯性肥胖症血清瘦素 (Leptin)及其临床意义。方法 :用ELISA法检测 48例单纯性肥胖症 (体重指数≥ 2 5 )和 40例健康对照者的血清Leptin水平。结果 :肥胖症组血清瘦素水平明显高于健康对照组 (P <0 .0 0 1) ,女性几乎较男性高 2倍以上。瘦素与BMI及脂肪含量呈正相关 (相关系数r分别为男性r =0 .36 ,0 .33 ,P <0 .0 5 ;女性r =0 .90 ,0 .87,P <0 .0 5 )。结论 :单纯性肥胖症血清瘦素水平升高 ,提示瘦素抵抗存在 ,可能在肥胖的发生发展中起重要作用