Comparison of insulin secretion and insulin sensitivity between normal and impaired glucose tolerance subjects with normal fasting plasma glucose

To examine glucose-stimulated insulin secretion and insulin sensitivity in the normal subjects and patients with impaired glucose tolerance, we performed the oral glucose tolerance test (OGTT) and modified insulin suppression test in 34 non-obese subjects. The plasma glucose and insulin concentrations were measured during fasting and every 30 min up to 120 min following 75 g of oral glucose loading. Ten subjects were classified as impaired glucose tolerance (IGT), and 24 subjects were as having normal glucose tolerance. In addition, the insulin-stimulated glucose uptake was estimated in all subjects by measuring the final 30 min steady-state plasma glucose (SSPG) of a continuous infusion of somatostatin, insulin and glucose for 4 hours (modified insulin suppression test). The mean plasma glucose concentrations of fasting and 60, 90, 120 min during OGTT study were significantly higher in the IGT subjects than in the normals. In addition, the mean incremental glucose areas under the curve during OGTT study were also greater in the IGT subjects than in the normals. The mean serum insulin concentrations were significantly higher at 90 and 120 minutes in the IGT patients than in the normals. During the modified insulin suppression test, the mean SSPG concentrations were significantly higher in the IGT patients than in the normals under the similar steady-state plasma insulin in both groups. There was a good correlation between the incremental insulin areas under the curve (OGTT) and the SSPG in the normal subjects (p less than 0.0001).(ABSTRACT TRUNCATED AT 250 WORDS)     

Propranolol pharmacokinetics during the menstrual cycle

The pharmacokinetics of propranolol during menstruation and in the mid menstrual cycle have been studied in nine young women taking a single 80 mg tablet on each occasion. There were wide between-individual differences in the serum concentration at any given time (4-5 fold at peak concentrations) but the serum concentration time curves within individuals showed only mild variations. The differences between the average pharmacokinetic parameter estimates for the group did not differ significantly between the two periods of study.     

Lymphocytes and perforin expression in endometrium during the menstrual cycle

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正常月经周期子宫内膜淋巴细胞的研究

采用免疫组化技术研究增殖期、分泌早期、分泌中期、分泌晚期子宫内膜中淋巴细胞的分布、表型特征及各类淋巴细胞数量的变化。结果表明：各期子宫内膜中Ｔ总淋巴细胞（ＣＤ＋３Ｔ淋巴细胞）、抑制或杀伤Ｔ淋巴细胞（ＣＤ＋８Ｔ淋巴细胞）、辅助Ｔ淋巴细胞（ＣＤ＋４Ｔ淋巴细胞）数量较少，不随月经周期而变化，子宫内膜中数量较多的并随月经周期变化的淋巴细胞ＣＤ＋５６大颗粒淋巴细胞，此细胞从增殖期至分泌晚期数量增加。提示正常月经周期子宫内膜淋巴细胞分布有其特殊规律，可能参与月经来潮与胚胎着床。     

Drug-induced QT prolongation in women during the menstrual cycle

Context  Women have a higher incidence of torsades de pointes than men, but it is not known if the risk of drug-induced torsades de pointes varies during the menstrual cycle. Objectives  To determine if the degree of QT prolongation in response to ibutilide varies with the menstrual cycle phase and to compare QT prolongation between women and men. Design and Setting  Cohort study of men and women who received the same intervention conducted between November 1998 and November 2000 at a general clinical research center of a university hospital. Participants  A volunteer sample of 58 healthy adults (38 men and 20 women) aged 21 to 40 years. Intervention  A low dose of ibutilide (0.003 mg/kg), infused intravenously for 10 minutes. Subjects were monitored for 120 minutes. Women received the intervention on 3 separate occasions to correspond with menstrual cycle phases, which were verified by using hormonal assays. Main Outcome Measure  QT interval, recorded from electrocardiogram at timed intervals during and after ibutilide infusion and standardized for variations in heart rate (QTc). Results  Maximum (mean [SD]) millisecond increase in QTc after ibutilide infusion was greater for women during menses (63 [13]) and the ovulatory phase (59 [17]) compared with women during the luteal phase (53 [14]) and compared with men (46 [16]; P = .002 vs menses and P = .007 vs ovulation). Progesterone (r = -0.40) and progesterone-to-estradiol ratio (r = -0.41), but not estradiol (r = 0.14) or testosterone (r = 0.09), were inversely correlated with ibutilide-induced QT prolongation. Conclusions  Menstrual cycle and sex differences exist in QTc responses to ibutilide, with the greatest increase in QTc corresponding to the first half of the menstrual cycle.      

Association between smoking, pancreatic insulin secretion and insulin resistance in Chinese subjects with or without glucose intolerance

Background  There are studies suggesting smoking may increase the risk of type 2 diabetes. Effects of smoking on insulin secretion and insulin resistance (IR) are, however, controversial.
Methods  This is a cross-sectional study. Since there were very few smokers among Hong Kong Chinese women, only men (n=1068) were analyzed in this report. Fasting and 2-hour plasma glucose and insulin were measured. Insulinogenic index as well as beta-cell function and IR based on homeostatic model assessment (HOMA) by computer model (HOMA Calculator v2.2) were calculated.
Results  Of the 1068 men, 147 had newly diagnosed diabetes, 131 newly diagnosed impaired glucose tolerance (IGT) and 790 were non-diabetic normal controls. Smokers had similar fasting and 2-hour insulin levels, insulinogenic index and HOMA derived beta-cell function as compared to non-smokers in the groups with diabetes, IGT or normal oral glucose tolerance test (OGTT). IR was also similar between smokers, ex-smokers and non-smokers in those with normal OGTT. In men with IGT or diabetes, after adjustment for age and body mass index, smokers were more insulin resistant as compared to non-smokers (IR, IGT: 1.59±1.07 vs 1.03±0.54, P<0.05; diabetes: 1.96±1.36 vs 1.06±0.45, P<0.01). With Logistic regression analysis, comparing smokers and non-smokers, IR was independently associated with smoking (odds ratio (95% CI), IGT: 2.23 (1.05, 4.71); diabetes: 3.92 (1.22, 12.58)). None of the other insulin parameters enter into the model among those with normal OGTT or comparing ex-smokers and non-smoker or smokers and ex-smokers.
Conclusions  In Chinese men, smoking did not show any direct association with insulin levels and pancreatic insulin secretion. Smoking men with IGT or diabetes appeared more insulin resistant than their non-smoking counterparts.

     

血糖波动对糖尿病大鼠胰岛素释放和胰岛素敏感性的影响

目的:观察血糖波动对糖尿病大鼠胰岛素释放和胰岛素敏感性的影响.方法:GK大鼠22只,随机分为糖尿病高血糖组、糖尿病血糖波动组,Wistar大鼠11只作为正常对照组,进行葡萄糖耐量实验(IPGTT)及在体胰岛分离后体外葡萄糖刺激下胰岛素释放实验(GSIS),并检测胰岛素相关基因的表达,以了解β细胞的胰岛素释放功能,进行胰岛素耐量试验以检测胰岛素敏感性的情况.结果:实验6周后血糖波动组和持续高血糖组体重无统计学差异.血糖波动组空腹血糖,糖负荷后15、30、60、120 min血糖,糖曲线下面积(AUCG)均高于持续高血糖组(P均<0.05).在体胰岛分离后体外葡萄糖刺激下胰岛素释放指数明显低于持续高血糖组(P均<0.05).血糖波动组胰岛素基因ins-1、ins-2和pdx-1表达及胰岛素敏感性较持续高血糖组显著降低(P均<0.05).结论:血糖波动使GK大鼠胰岛素释放功能降低并且胰岛素相关基因表达减少可能是胰岛素释放减少的原因之一,血糖波动使胰岛素敏感性降低.     

双调蛋白在人体子宫内膜组织中的表达特征

目的:研究双调蛋白在人体子宫内膜组织中的表达特征.方法:取增殖期和分泌期的人体子宫内膜,采用实时定量RT-PCR方法,检测双调蛋白mRNA在子宫内膜增殖期和分泌期的表达差异;采用原位杂交和免疫组织化学的方法,从基因和蛋白水平检测双调蛋白在人体子官内膜组织中的表达特征.结果:定量RT-PCR结果显示,双调蛋白mRNA在增殖期和分泌期的子宫内膜均有表达,在分泌期其表达量显著升高,是增殖期的32倍.原位杂交和免疫组织化学结果显示,双调蛋白主要分布于子宫内膜腺体,定位于细胞浆内;双调蛋白mRNA在增殖期和分泌期子宫内膜的表达分别为0.54±0.22和2.96±0.47(P<0.01);双调蛋白在增殖期和分泌期子宫内膜的表达分别为0.77±0.47和2.60±0.43(P<0.01).双调蛋白在分泌期子宫内膜中的表达显著升高,与荧光定量RT-PCR分析的结果相符.结论:双调蛋白在子宫内膜分泌期的表达显著增加,提示该蛋白可能与子宫内膜细胞分化或胚胎着床有关.