Effects of galanin on insulin and glucagon secretion in the rat

Galanin-like immunoreactivity has been visualized in nerve fibers in the islets of Langerhans, suggesting an involvement of galanin in the neural regulation of islet function. In this study, we investigated the effects of galanin on basal and stimulated insulin and glucagon secretion by infusing the peptide at three different dose rates in rats. We also studied the direct effect of galanin on insulin secretion from freshly isolated rat islets. At 320 pmol/kg/min, but not at 20 or 80 pmol/kg/min, galanin lowered basal plasma insulin levels. In contrast, basal plasma glucagon levels were lowered by galanin already at 20 and 80 pmol/kg/min. Furthermore, galanin inhibited both glucose- and arginine-induced insulin release at all three dose levels, whereas arginine-induced glucagon release was not affected by galanin. Glucose-stimulated insulin secretion from isolated rat islets was dose-dependently suppressed by galanin (10^-6-10^-8M). Therefore, it is concluded that galanin in rats inhibits insulin secretion, both in vivo and in vitro, and that at lower dose levels, the peptide also inhibits basal glucagon release.     

Leptin, lipid and lipid metabolism-related hormones in chronic renal failure in Arabia

SUMMARY: In patients with chronic renal failure (CRF), hyperleptinaemia has been widely reported, but the exact mechanisms leading to elevated leptin levels are unclear. Impaired renal clearance of leptin and the influence of other hormones may be important. In this study, we measured serum leptin levels in 150 patients on haemodialysis, peritoneal dialysis or in the predialysis phase of CRF. Furthermore, we measured plasma levels of insulin, growth hormone (GH) and insulin-like growth factor 1 (IGF-1), as well as plasma levels of triacylglycerols and total low density lipoprotein (LDL)- and high density lipoprotein (HDL)-cholesterol. We observed significantly elevated levels of leptin, particularly in female patients, and leptin was shown to correlate significantly with insulin, total and LDL-cholesterol and log triacylglycerols. Leptin was inversely correlated with GH concentrations, but was not correlated with IGF-1 levels. Despite the multiple correlations established between leptin levels and other variables, only hyperinsulinaemia in CRF seems to be important as a determinator of leptin levels.     

Prior diabetes mellitus is associated with increased morbidity in cystic fibrosis patients undergoing bilateral lung transplantation: an ‘orphan’ area? A retrospective case–control study

Background: The aim of this study was to determine whether pre-existing diabetes mellitus increases the risk of rejection, infection and/or death in cystic fibrosis patients undergoing bilateral sequential single-lung transplantation.
Methods: A retrospective audit of 25 consecutive patients with cystic fibrosis who underwent bilateral sequential single-lung transplantation between 1 January 2003 and 31 December 2005 at a tertiary referral hospital was carried out.
Results: Although 32% patients had diabetes diagnosed before lung transplantation, 92% had random blood glucose levels ≥11.1 mmol/L requiring insulin during admission. Patients with pre-existing diabetes had increased infection-related (3.9 vs 1.2, P = 0.01) and putative rejection-related (1.4 vs 0.5, P = 0.04) hospital admissions post-transplantation compared with those without diabetes pre-transplant. During the period of observation, four of eight patients with a prior diagnosis of diabetes died compared with none of 17 patients without prior diabetes ( P = 0.0055).
Conclusion: Almost all cystic fibrosis patients develop hyperglycaemia after lung transplantation, but patients with prior diabetes have more complication-related admissions to hospital and a higher mortality rate.     

Aspart与正规人胰岛素应用胰岛素泵控制血糖的疗效比较

选择21例应用预混人胰岛素Novolin 30R治疗血糖控制欠佳的1型和2型糖尿病患者，用胰岛素泵交叉应用相同剂量的速效人胰岛素类似物Aspart与正规人胰岛素NovolinR控制高血糖，比较两种药物应用期间全天毛细血管血糖谱，发现Aspart在控制空腹血糖、餐后血糖及全天平均血糖均较后者疗效为佳。     

Diabetes mellitus and open heart surgery

A method, based on bedside determinations of blood glucose by nursing staff, was designed to control the administration of insulin to diabetic patients during and following open heart surgery. A computer-controlled intravenous infusion pump was used to deliver the insulin. Excellent control of the hyperglycaemia normally associated with open heart surgery was achieved, with 84 percent of measured blood glucose values falling within 2 mmol/litre of the target value of 6 mmol/litre. The method proved to be simple, effective, and safe.     

Immune reactivity towards insulin, its amyloid and protein S100B in blood sera of Parkinson's disease patients

Peripheral immune responses can be sensitive indicators of disease pathology. We evaluated the autoimmune reactions to endocrine (insulin) and astrocytical (S100B) biomarkers in the blood sera of 26 Parkinson's disease (PD) patients compared with controls by using ELISA. We found a statistically significant increase of the autoimmune responses to both antigens in PD patients compared with controls with a mean increase of 70% and 50% in the autoimmune reactions towards insulin and S100B, respectively. Heterogeneity of the immune responses observed in patients may reflect the modulating effect of multiple variables associated with neurodegeneration and also changes in the basic mechanisms of individual autoimmune reactivity. We did not detect any pronounced immune reactions towards insulin amyloid fibrils and oligomers in PD patients, indicating that an amyloid-specific conformational epitope is not involved in immune recognition of this amyloid type, while sequential epitope of native insulin is hidden within the amyloid structures. Immune reactions towards S100B and insulin may reflect the neurodegenerative brain damaging processes and impaired insulin homeostasis occurring in PD.     

Severe hypoglycaemia in a person with insulin autoimmune syndrome accompanied by insulin receptor anomaly type B.

AIMS: A rare case of the insulin autoimmune syndrome (IAS) accompanied by insulin receptor anomaly is reported. METHODS: Antibodies to insulin and insulin receptor were determined in the patient with severe hypoglycaemia before and after the treatment with prednisolone. RESULTS: Titers of antibody to insulin and insulin receptors were 73.0% and 41.5%, respectively. Drug-induced lymphocyte stimulation tests were all negative for the suspicious drugs. Her HLA-DR was DRB1*0403/04051. Following steroid therapy, the formation of antibodies was suppressed and alleviated her symptoms. Scatchard analysis yielded findings specific to polyclonal antibodies. CONCLUSIONS: The changes in autoantibodies resulted in alleviation of the hypoglycemic symptoms as a result of steroid therapy.     

胰岛素抵抗和脑血管病关系的研究

目的：探讨胰岛素抵抗与脑梗死、脑出血的关系，为针对胰岛素抵抗的治疗可以有效地预防脑血管疾病提供理论依据。方法：选取42例脑梗死（脑梗死组）、40例脑出血（脑出血组）及30例非脑血管病患者（对照组），分别测定空腹胰岛素（FINS）、空腹血糖（FBG），计算胰岛素敏感指数（ISI），各组间进行比较。结果：脑梗死组和脑出血组患者ISI低于对照组（P〈0.05），而FINS高于对照组（P〈0．05），FBG与对照组差异无统计学意义（P〉0．05）。结论：胰岛素抵抗可能是脑血管病的一个重要危险因素。     

Adipose tissue and liver lipid metabolism in obese children: role of the body mass index and the presence of acanthosis nigricans.

AIMS: The aims of our study were to determine if insulin resistance is associated with increased plasma levels of non-esterified fatty acids (NEFA), glycerol, 3-hydroxybutyrate and triglycerides in obese children. We also studied whether the presence of acanthosis nigricans (AN) led to further alterations in the above parameters. METHODS: A total of 101 children were studied on their first visit to the paediatric endocrine clinic. Seventy-four were obese, 30 of them with AN. The remaining 27 were non-obese healthy children (control group). NEFAs, glycerol, triglycerides, 3-hydroxybutyrate, insulin, leptin, adiponectin and glucose were determined in blood samples obtained after overnight fasting. The insulin resistance index (IRI) was calculated following the homeostasis model assessment (HOMA). Data from the three groups were compared using appropriate statistical tests. RESULTS: No differences in age, sex ratio and pubertal stage were observed among the three groups. The group of children with the highest body mass index (BMI) showed higher plasma levels of insulin and leptin, higher IRI and lower plasma levels of adiponectin. As insulin and IRI increased, NEFA and 3-hydroxybutyrate decreased and triglycerides increased. When obese children were categorized by BMI, the presence of AN further exacerbated these differences. CONCLUSIONS: In obese children, insulin resistance is associated with plasma lipid alterations suggestive of both decreased adipose tissue lipolysis and hepatic beta-oxidation and increased hepatic synthesis of triglycerides. Such a metabolic condition may facilitate fat storage and hinder weight loss.     

荞麦花叶黄酮对2型糖尿病大鼠胰岛素抵抗及肝组织PTP1B的影响

目的:探讨荞麦花叶黄酮(FBFL)对2型糖尿病大鼠降血糖、改善胰岛素抵抗的作用及其机制.方法:雄性健康Wistar大鼠70只,随机抽取10只作为正常对照组,其余60只大鼠每天灌胃脂肪乳,第14天开始腹腔注射小剂量四氧嘧啶,隔日1次,共3次,同时继续灌胃脂肪乳.末次腹腔注射四氧嘧啶72 h后,用血糖仪测定空腹血糖和用K_(IPT)值判定胰岛素抵抗性.K_(IPT)＜正常组的60%作为2型糖尿病胰岛素抵抗大鼠.将成模大鼠随机分为模型组,阳性药物组,FBFL低、中、高剂量组,连续4周.末次给药后禁食,用血糖仪测空腹血糖(FBG),用正糖钳技术判定胰岛素抵抗性,用生化分析仪测定游离脂肪酸(FFA),放免法测定血浆胰岛素(INS),免疫组织化学法检测肝组织蛋白酪氨酸磷酸酶1B(PTP1B)表达.结果:与正常组比较,模型组大鼠FBG,INS,FFA含量明显升高(P＜0.135,P＜0.01);大鼠葡萄糖输注速率(GIR)明显下降;肝组织PTP1B表达增加.各剂量FBFL能不同程度的改善上述指标的变化,明显改善胰岛素抵抗性,增加胰岛素敏感性,使肝组织PTP1B表达下调,并呈一定剂量依赖性.结论:FBFL对四氧嘧啶加脂肪乳所致2型糖尿病大鼠胰岛素抵抗具有明显的改善作用,并呈一定剂量依赖性.