2型糖尿病患者血浆前胰岛素水平

目的 :通过检测前胰岛素水平来探讨 2型糖尿病患者高胰岛素血症的原因。方法 :采用放射免疫分析法测定 2型糖尿病患者和正常对照组血浆前胰岛素 (PIM)、胰岛素 (IRI)和 C肽 (CP)水平。结果 :2型 DM组空腹 PIM(2 7.89± 2 2 .37pmol/ L)、IRI(186 .6 3± 136 .97pmol/ L)水平和 PM/ IRI比值 (17.11± 9.35 % )均明显高于对照组 PIM (6 .75± 5 .6 2 pmol/ L ) .IRI(10 7.6 7± 2 6 .43pm ol/ L )水平和 PIM/ IRI比值 (5 .6 7±3.6 6 % ) (P均 <0 .0 1) ;两组之间空腹 C P水平差异无显著性意义 (6 83.1± 5 87.4pm ol/ L比 5 2 8.0±2 0 1.3pm ol/ L,P>0 .0 5 )。结论 :2型糖尿病患者的高胰素血症主要是高前胰岛素血症所致 ,可能是胰岛素抵抗的原因之一。     

(His)6-Arg-Arg-人胰岛素原在大肠杆菌中的高效表达

为了提高胰岛素原的表达量，用pQE-40质粒构建了(His)6-Arg-Arg-人胰岛素原[(His)6-Arg-Arg- human Proinsulin，RRhPI]的大肠杆菌表达系统。通过培养条件的优化，在摇瓶培养的条件下，目标产物：RRhPI以包涵体形式获得了高效表达，每升培养基收获湿菌体约27g，包涵体6g(干重1．8g)，RRhPI约540mg。该水平已超过现有文献报道的摇瓶培养的最高水平。     

The immunogenicity of insulin preparation. Antibody levels before and after transfer to highly purified porcine insulin

Summary Ninety-two insulin-dependent diabetics (aged 4–20 years, mean±SD: 13±4) with a duration of diabetes from 2 to 17 years (7±3) were transferred from Lente or NPH (5 × crystallised insulin) to Monotard insulin (highly purified insulin). Total serum immunoreactive insulin levels and concentrations of antibodies against insulin, porcine proinsulin, a-component and pancreatic polypeptide were determined prior to [I] and at a mean of 220 [II], 460 [III], 830 [IV], and 1170 [V] days after the change. All but two subjects had insulin antibodies (IgG) at the start, with a mean value of 2864 U/ml. There was a significant fall in the mean insulin antibody level between [I] and [II] to 2165 U/ml (p<10^-7), followed by an increase between [II] and [III] whereafter a slight decrease was observed being significant between [III] and [IV], as well as between [IV] and [V] (p<0.05); some patients showed a constant fall over the entire period, while others showed fluctuations. Total serum insulin showed a similar pattern, with a mean value of 1141 U/ml at [I] declining to 522 U/ml at [V]. The percentage fall between [I] and [V] was greater (54%) than that in the insulin antibodies (30%). Antibodies against acomponent, proinsulin and pancreatic polypeptide were present in 96%, 72% and 41% of the patients respectively before the change in therapy. There was a decline in these antibodies between each sampling (p values between <10^-3 and 10^-8) and, at the end of the investigation antibodies against a-component were above the detection limit in only 4 patients, and none of the patients showed antibodies against proinsulin or pancreatic polypeptide. Thus, removal of the impurities, including the hormonal contaminants of insulin, leads to a slow fall in antibodies to insulin and a much faster disappearance of antibodies against acomponent, proinsulin and pancreatic polypeptide.     

The effect of maternal caffeine ingestion on pancreatic function in the neonatal rat

Summary Pancreatic function was investigated in neonatal suckling offspring of caffeine-ingesting dams, with or without maternal sucrose supplementation, throughout pregnancy and lactation. In offspring of rats ingesting caffeine without sucrose supplementation, there was initial hyperinsulinaemia, followed by a progressive fall of plasma insulin to subnormal levels. This fall in plasma insulin coincided with depletion of pancreatic insulin stores. Both the fall in plasma insulin and depletion of pancreatic insulin stores were prevented by sucrose supplementation of caffeine-ingesting dams. Offspring of dams fed sucrose alone and control offspring also maintained pancreatic insulin stores and circulating insulin levels over the first 14 days of postnatal life. Pancreases from offspring of caffeine-exposed animals tested in vitro showed enhanced sensitivity of the insulin release process to glucose. This was reflected in the glucose concentration required to elicit half-maximal insulin release (2.4 ± 0.2 mmol/l for caffeine offspring, 2.3 ± 0.2 mmol/l for caffeine with sucrose, 3.8 ± 0.3 mmol/l for sucrose and 4.1 ± 0.3 mmol/l for control offspring, mean ± SEM). In contrast, offspring of sucrose-supplemented (with or without caffeine) dams showed increased sensitivity of the proinsulin biosynthetic process to glucose, whereas offspring of dams ingesting caffeine alone showed no significant enhancement of the biosynthetic process compared with control offspring. Thus enhanced sensitivity of the insulin secretory process to glucose without a change in the sensitivity of the biosynthetic process in the offspring of the caffeine ingesting (nonsucrose supplemented) dams could explain the progressive depletion of pancreatic insulin stores and eventual hypoinsulinaemia seen in this group.     

简捷的PCR点突变实现人胰岛素原基因非β细胞表达

利用聚合酶链反应 (PCR)技术将人胰岛素原基因进行两处突变 ,引入Furin酶的裂解位点 ,再构建突变人胰岛素原基因逆转录病毒载体重组质粒 ,转染HepG2肝癌细胞 ,经检测可表达成熟胰岛素。所采用的PCR点突变法简单且无错误掺入产生     

Precipitin reactions between insulin,proinsulin, insulin chains and insulin antibody

Summary Insulin antibody was produced in guinea pigs and the precipitins tested by double diffusion in agarose gel. Pork, beef and monocomponent insulin produced precipitin lines. Proinsulin also produced a precipitin line with these antisera but no lines appeared with either the A-chain or the B-chain of insulin. There was good correlation between the precipitin titre and the radioimmunoassay titre.     

Fasting proinsulin and 2-h post-load glucose levels predict the conversion to NIDDM in subjects with impaired glucose tolerance: The Hoorn Study

Summary The aims of the present study were to observe the natural history of impaired glucose tolerance and to identify predictors for development of non-insulin-dependent diabetes mellitus (NIDDM). A survey of glucose tolerance was conducted in subjects aged 50–74 years, randomly selected from the registry of the middle-sized town of Hoorn in the Netherlands. Based on the mean values of two oral glucose tolerance tests subjects were classified in categories of glucose tolerance according to the World Health Organization criteria. All subjects with impaired glucose tolerance (n=224) were invited to participate in the present study, in which 70% (n=158) were subsequently enrolled. During follow-up subjects underwent a repeated paired oral glucose tolerance test. The mean follow-up time was 24 months (range 12–36 months). The cumulative incidence of NIDDM was 28.5% (95% confidence interval 15–42%). Age, sex, and anthropometric and metabolic characteristics at baseline were analysed simultaneously as potential predictors of conversion to NIDDM using multiple logistic regression. The initial 2-h post-load plasma glucose levels and the fasting proinsulin levels were significantly (p<0.05) related to the incidence of NIDDM. Anthropometric characteristics, the 2-h post-load specific insulin levels and the fasting proinsulin/fasting insulin ratio were not related to the incidence of NIDDM. These results suggest that beta-cell dysfunction rather than insulin resistance plays the most important role in the future development of diabetes in a high-risk Caucasian population.Abbreviations IGT Impaired glucose tolerance - NIDDM non-insulin-dependent diabetes mellitus - OGTT oral glucose tolerance test - CI confidence interval - W/H ratio waist/hip ratio - BMI body mass index - OR odds ratio     

Identification of prediabetes in first-degree relatives at intermediate risk of type I diabetes

Prevention trials of type I diabetes are limited by recruitment of individuals at high risk of the disease. We investigated whether demographic and biological characteristics can identify rapid progressors among first-degree relatives of known patients at intermediate (< 10%) 5-year risk. Diabetes-associated antibodies, random proinsulin : C-peptide (PI/C) ratio and HLA DQ genotype were determined (repeatedly) in 258 islet antibody-positive IA-2Antibody-negative (Abpos/IA-2Aneg) normoglycaemic first-degree relatives. During follow-up (median 81 months), 14 of 258 Abpos/IA-2Aneg relatives developed type I diabetes; 13 (93%) of them had persistent antibodies conferring a 12% [95% confidence interval (CI): 5-19%] 5-year risk of diabetes. In Abpos/IA-2Aneg relatives with persistent antibodies (n = 126), the presence of >/= 1 HLA DQ susceptibility haplotype in the absence of a protective haplotype (P = 0.033) and appearance on follow-up of a high PI/C ratio (P = 0.007) or IA-2A-positivity (P = 0.009) were identified as independent predictors of diabetes. In persistently antibody-positive relatives with HLA DQ risk a recurrently high PI/C ratio or development of IA-2A identified a subgroup (n = 32) comprising 10 of 13 (77%) prediabetic relatives and conferred a 35% (95% CI: 18-53%) 5-year risk. Under age 15 years, 5-year progression (95% CI) was 57% (30-84%) and sensitivity 62%. In the absence of IA-2A, the combination of antibody persistence, HLA DQ risk and elevated PI/C ratio or later development of IA-2A and young age defines a subgroup of relatives with a high risk of type I diabetes (>/= 35% in 5 years). Together with initially IA-2A-positive relatives these individuals qualify for standardized beta cell function tests in view of prevention trials.     

Birth weight and the insulin resistance syndrome: association of low birth weight with truncal obesity and raised plasminogen activator inhibitor-1 but not with abdominal obesity or plasma lipid disturbances

Abstract Aims/hypothesis. To distinguish the physiological disturbances related to birth weight from the cluster of disturbances called the insulin resistance syndrome.?Methods. Men participating in a population-based study in Uppsala, Sweden, with recordings of birth weight, were metabolically characterised at age 50 (n = 1268) and re-investigated at age 70 (n = 734). Blood pressure, BMI, glucose and insulin concentrations are associated with birth weight in this cohort.?Results. Birth weight was inversely associated (p < 0.03) with subscapular:triceps skinfold ratio (truncal fat), plasminogen activator inhibitor-1 (PAI-1) activity, specific insulin and proinsulin-like molecules when adjusted for BMI. Birth weight was not related (p > 0.10) with waist circumference, serum triglycerides or HDL cholesterol. The insulin resistance syndrome was defined as the combination of hypertension, insulin resistance and dyslipidaemia. The prevalence of this syndrome at age 50 and 70 was inversely related to birth weight with odds ratio 0.66 and 0.71, respectively, per kg increase in birth weight. When the syndrome was defined to include truncal obesity or raised plasminogen activator inhibitor-1 instead of dyslipidaemia, the corresponding odds ratios were 0.51 and 0.66, respectively.?Conclusions/interpretation. Low birth weight predicts high blood pressure, insulin resistance, truncal obesity and high plasminogen activator inhibitor-1 activity but not the abdominal obesity or dyslipidaemia present in the insulin resistance syndrome. The cluster of disturbances associated with low birth weight is a subset of the disturbances that are clustered in the general population as the insulin resistance syndrome. This subset of physiological disturbances is possibly linked by a specific pathway. [Diabetologia (2000) 43: 54–60] Received: 14 May 1999 and in revised form: 15 July 1999