Resistin, a newly discovered peptide hormone mainly secreted by adipose tissues, is present at high levels in serum of obese mice and may be a potential link between obesity and insulin resistance in rodents. However, some studies of rat and mouse models have associated insulin resistance and obesity with decreased resistin expression. In humans, no relationship between resistin level and insulin resistance or adiposity was observed. This suggests that additional studies are necessary to determine the specific role of resistin in the regulation of energy metabolism and adipogenesis. In the present study, we investigated the effect of resistin in vivo on glucose and lipid metabolism by over-expressing resistin in mice by intramuscular injection of a recombinant eukaryotic expression vector pcDNA3.1-Retn encoding porcine resistin gene. After injection, serum resistin and serum glucose (GLU) levels were significantly increased in the pcDNA3.1-Retn-treated mice; there was an obvious difference in total cholesterol (TC) level between the experiment and the control groups on Day 30. In pcDNA3.1-Retn-treated mice, both free fatty acid (FFA) and high density lipoprotein (HDL) cholesterol levels were markedly lower than those of control, whereas HDL cholesterol and triglyceride (TG) levels did not differ between the two groups. Furthermore, lipase activity was expressly lower on Day 20. Our data suggest that resistin over-expressed in mice might be responsible for insulin resistance and parameters related to glucose and lipid metabolism were changed accordingly.
Animals ; Blood Glucose ; analysis ; Cholesterol, HDL ; blood ; Cholesterol, LDL ; blood ; Fatty Acids, Nonesterified ; blood ; Glucose ; metabolism ; HeLa Cells ; Humans ; Lipid Metabolism ; Male ; Mice ; Resistin ; blood ; physiology ; Triglycerides ; blood

Glycated haemoglobins are haemoglobins with an attached sugar moiety. They constitute the HbA1 fraction of the adult haemoglobin HbA. HbA1c is the predominant fraction of HbA1 and gives an estimate of the blood sugar levels of an individual over the last three months. It has been observed that an HbA1c value of less than seven percent reduces the microvascular complications in diabetic patients. However, HbA1c is not affected by blood sugar levels alone. Apart from blood sugar, there are other factors that affect HbA1c. This article reviews in detail the structure, formation, methods of measurement, factors affecting HbA1c levels and their clinical significance.
Blood Glucose ; metabolism ; Diabetes Mellitus ; metabolism ; physiopathology ; Glycated Hemoglobin A ; analysis ; metabolism ; Humans

BACKGROUND: Commutable reference materials (RMs) are suitable for end-users for evaluating the metrological traceability of values obtained using routine measurement systems. We assessed the performance of 6 routine measurement systems with validated secondary RMs. METHODS: We tested the homogeneity, stability, and commutability of 5 minimally processed human serum pools according to the standard guidelines. The serum pools were assigned values as per the reference procedure of the United States Centers for Disease Control and were used to evaluate the trueness of results from 6 commercial measurement systems based on enzymatic methods: 3 glucose oxidase (GOD) and 3 hexokinase (HK) methods. RESULTS: The prepared RMs were validated to be sufficiently homogenous, stable, and commutable with the patient samples. Method bias varied for different systems: GOD01, -0.17 to 2.88%; GOD02, 1.66 to 4.58%; GOD03, -0.17 to 3.14%; HK01, -3.48 to -0.85%; HK02, -3.83 to -0.11%, and HK03, -1.82 to -0.27%. CONCLUSIONS: We observed that the prepared serum glucose RMs were qualified for trueness assessment. Most of the measurement systems met the minimal quality specifications.
Blood Chemical Analysis/instrumentation/*standards ; Blood Glucose/*analysis ; Glucose Oxidase/metabolism ; Hexokinase/metabolism ; Humans ; Reagent Kits, Diagnostic ; Reference Standards ; Regression Analysis

OBJECTIVETo study the feasibility of monoamine neurotransmitters, serum glucose, serum glycerinate and cholesterol as objective indices for evaluating occupational stress.

METHODSJob stressors, modifiers, job strains in 844 people with four kinds of occupation were investigated, and the concentration of monoamine neurotransmitters, glucose, glycerinate and cholesterol in blood were detected at the same time. The methods of multiple stepwise regression and covariance analysis were used to analyze the data.

RESULTSThere was close relationship between monoamine neurotransmitters and job stressors, the forecast of the equation of 5-hydroxytryptamine (5-HT), dopamine (DA) and norepinephrine (NE) was 0.7238, 0.5703, 0.4438 respectively, the critical values of them were 804.00, 226.00 and 275.00 ng/ml respectively. There was a little contribution of job stressors to the equation of glucose, glycerinate and cholesterol, the critical values were 6.40, 2.51 and 5.92 mmol/L respectively.

CONCLUSIONMonoamine neurotransmitters may be a direct objective evaluating indices. Sugar, glycerinate and cholesterol may be an indirect objective indices.

Adult ; Blood Glucose ; analysis ; Cholesterol ; blood ; Female ; Humans ; Male ; Middle Aged ; Neurotransmitter Agents ; blood ; Occupational Diseases ; metabolism ; Stress, Psychological ; metabolism

BACKGROUNDThe delivery of glucose from the blood to the brain involves its passage across the endothelial cells of the blood-brain barrier (BBB), which is mediated by the facilitative glucose transporter protein 1 (GLUT(1)), and then across the neural cell membranes, which is mediated by GLUT(3). This study aimed to evaluate the dynamic influence of hyperglycemia on the expression of these GLUTs by measuring their expression in the brain at different blood glucose levels in a rat model of diabetes. This might help to determine the proper blood glucose threshold level in the treatment of diabetic apoplexy.

METHODSDiabetes mellitus was induced with streptozotocin (STZ) in 30 rats. The rats were randomly divided into 3 groups: diabetic group without blood glucose control (group DM1), diabetic rats treated with low dose insulin (group DM2), and diabetic rats treated with high dose insulin (group DM3). The mRNA and protein levels of GLUT(1) and GLUT(3) were assayed by reverse transcriptase-polymerase chain reaction (RT-PCR) and immunohistochemistry, respectively.

RESULTSCompared with normal control rats, the GLUT(1) mRNA was reduced by 46.08%, 29.80%, 19.22% (P < 0.01) in DM1, DM2, and DM3 group, respectively; and the GLUT(3) mRNA was reduced by 75.00%, 46.75%, and 17.89% (P < 0.01) in DM1, DM2, and DM3 group, respectively. The abundance of GLUT(1) and GLUT(3) proteins had negative correlation with the blood glucose level (P < 0.01). The density of microvessels in the brain of diabetic rats did not change significantly compared with normal rats.

CONCLUSIONSChronic hyperglycemia downregulates GLUT(1) and GLUT(3) expression at both mRNA and protein levels in the rat brain, which is not due to the decrease of the density of microvessels. The downregulation of GLUT(1) and GLUT(3) expression might be the adaptive reaction of the body to prevent excessive glucose entering the cell that may lead to cell damage.

Animals ; Blood Glucose ; analysis ; Brain ; metabolism ; Diabetes Mellitus, Experimental ; metabolism ; Glucose Transporter Type 1 ; analysis ; genetics ; Glucose Transporter Type 3 ; analysis ; genetics ; Glycated Hemoglobin A ; analysis ; Male ; RNA, Messenger ; analysis ; Rats ; Rats, Wistar ; Streptozocin

BACKGROUNDThe hypothalamus plays a central role in the regulation of metabolism by sensing metabolic demands and releasing regulatory neurotransmitters. This study investigated the response of the hypothalamus to glucose ingestion in rats by blood oxygen level-dependent functional magnetic resonance imaging (BOLD-fMRI) and immunohistochemical techniques to determine the role of the hypothalamus in glyco-regulation during disturbances in carbohydrate metabolism.

METHODSThe signal intensity of the hypothalamus was monitored by fMRI for 60 minutes after oral glucose intake in 48 healthy rats (age 14 months), which included 24 normal weight rats (weighing (365 +/- 76.5) g) and 24 overweight rats (weighing (714 +/- 83.5) g). Then, 12 rats (6 normal, 6 overweight) underwent a repeat fMRI scan after consuming an equivalent amount of water without glucose on a separate day. The procedure for fMRI with water intake was the same as for glucose ingestion. fMRI data was processed using time cluster analysis and intensity averaging method. After fMRI, the expression of neuropeptide Y (NPY) and 5-hydroxytryptamine (5-HT) in the hypothalamus of all rats was determined by immunohistochemistry. Positive cells for NPY or 5-HT were counted.

RESULTSThere was a transient, but significant, decrease in fMRI signal intensity in all rats (mean (3.12 +/- 0.78)%) in the hypothalamus within 19.5 - 25.5 minutes of oral glucose ingestion. In overweight rats, the decrease in signal intensity in response to the glucose ingestion was more markedly attenuated than that observed in normal weight rats ((2.2 +/- 1.5)% vs (4.2 +/- 0.7)% inhibition, t = 2.12, P < 0.05). There was no significant response in the hypothalamus after oral water ingestion. The percentage of NPY positive cells in obese rats were slightly lower than those in control group (21% vs 23%, t = 0.71, P > 0.05); but there was no significant difference between the two groups; the percentage of 5-HT positive cells in obese rats were significantly lower than those in the control group (22% vs 31%, t = 3.25, P < 0.01).

CONCLUSIONSThere is a transient, but significant, decrease in BOLD signal intensity in the hypothalamus following glucose ingestion, which is similar to that observed in humans. The response of the hypothalamus to glucose ingestion was different in overweight and normal weight rats. The percentage of NPY positive cells in obese rats were lower than those in the control group, although this difference was not statistically significant. The percentage of 5-HT positive cells in obese rats was significantly lower than those in the control group.

Animals ; Glucose ; metabolism ; Hypothalamus ; physiology ; Immunohistochemistry ; Magnetic Resonance Imaging ; methods ; Neuropeptide Y ; analysis ; Obesity ; metabolism ; Oxygen ; blood ; Rats ; Serotonin ; analysis

Blood Glucose ; analysis ; Capillaries ; metabolism ; Humans ; Hypoglycemia ; diagnosis ; Infant, Newborn ; Neonatal Screening ; methods ; Reference Standards

BACKGROUND: With the advent of sodium glucose co-transporter 2 inhibitors to control glucose and treat diabetes, laboratory data aided by either timed or spot glucose levels in the urine could be used as an alternative marker of drug response. The aim of this study was to assess the agreement between overnight urinary glucose excretion (UGE) and morning spot urinary glucose-to-creatinine ratio (UGCR). METHODS: In this prospective cross-sectional study, we enrolled a total of 215 participants with either normal glucose tolerance (NGT), pre-diabetes, or type 2 diabetes mellitus (T2DM). To exclude external factors such as food intake and physical activity, urine samples collected overnight at an 8-hr interval and the first-voided morning spot urine were collected and compared. RESULTS: The median values of overnight 8-hr UGE in participants with NGT (N=14), pre-diabetes (N=41), and T2DM (N=160) were 35.0 mg, 35.6 mg, and 653.4 mg, respectively. In participants with T2DM, the median values of overnight 8-hr UGCR and first-voided morning spot UGCR (M-UGCR) were 1.37 mg/mg and 0.16 mg/mg, respectively. Quantitative analyses using an intraclass correlation coefficient (ICC) demonstrated a good reliability of measurement of the overnight 8-hr UGCR and M-UGCR (ICC=0.943, P<0.001). The M-UGCR was also significantly related to the overnight 8-hr UGE (r=0.828, P<0.001). CONCLUSIONS: M-UGCR and overnight 8-hr UGCR showed good agreement, suggesting that M-UGCR be used as a simple index for estimating overnight amounts of UGE in patients with T2DM.
Adult ; Aged ; Blood Glucose/analysis ; Creatinine/*urine ; Cross-Sectional Studies ; Diabetes Mellitus, Type 2/*pathology ; Female ; Glucose/*analysis/metabolism ; Humans ; Linear Models ; Male ; Middle Aged ; Prospective Studies ; Urinalysis

OBJECTIVE: The brain is dependent on glucose as an energy source. Intricate homeostatic mechanisms have been implicated in maintaining the blood glucose concentration in the brain. The aim of this study is to find the way to identify the metabolic proteins regulating the glucose in rat hypothalamus. METHODS: In this study, we analysed the secretome from rat hypothalamus in vivo. We introduced 500 nM of insulin into the rat hypothalamus. The chromatographic patterns of the secretome were identified, after which Mass Spectrometry-Mass Spectrometry (MS-MS) analysis was performed. RESULTS: In Liquid Chromatography-Mass Spectrometry (LC-MS) analysis, 60 proteins were identified in the secretome. Among them, 8 novel proteins were unveiled and were associated with the energy metabolism of insulin signaling in mitochondria of rat hypothalamic neuron. Nineteen other proteins have unknown functions. These ligands were confirmed to be secreting from the rat hypothalmus on insulin signaling by western blotting. CONCLUSION: The hypothalamus is the master endocrine gland responsible for the regulation of various physiological and metabolic processes. Proteomics using LC-MS analysis offer a efficient means for generating a comprehensive analysis of hypothalamic protein expression by insulin signaling.
Animals ; Blood Glucose ; Blotting, Western ; Brain ; Chromatography, Liquid ; Endocrine Glands ; Energy Metabolism ; Glucose ; Hypothalamus ; Insulin* ; Ligands ; Mass Spectrometry ; Metabolism ; Mitochondria ; Neurons ; Proteomics ; Rats* ; Spectrum Analysis* ; Tandem Mass Spectrometry

OBJECTIVEHigh-sensitivity C-reactive protein (hs-CRP) may predict the development of type 2 diabetes mellitus (T2DM), metabolic syndrome (MS) and cardiovascular diseases (CVD) in adult, but few reports on relevant studies in children are available. The present study aimed to understand possible correlation between serum hs-CRP levels and some factors of obese children and adolescents with or without impaired glycometabolism.

METHODSSeventy obese children and adolescents (age 8 - 17 years) and 30 non-obese healthy controls (group 1, 20 boys and 10 girls, mean age 12.6 years) were enrolled into this study. The obese individuals were subdivided into two groups according to the results of oral glucose tolerance test: the obese subjects without IGR (group 2, 54 cases, 43 boys and 11 girls, mean age 11.3 years) and the obese subjects with impaired glycometabolism (group 3, 16 cases, 8 boys and 8 girls, mean age 12.8 years). The levels of serum parameters including hs-CRP, glucose, lipid, insulin, C-peptide and whole blood HbA1c were determined. SPSS 10.0 was used for statistical analysis.

RESULTS(1) There was significant increase of serum hs-CRP level in obese children and adolescents, the median was 2.44 (0.01 - 14.6) mg/L; the level of control group was 0.1 (0.01 - 2.1) mg/L. (2) Some of the following parameters, such as fasting plasma glucose (FPG), triglyceride (TG), fasting insulin (FINS), C-peptide (Cp) and insulin resistance index (IRI), were found increased in group 2 and 3 as compared to group 1. When FPG and TG were still in normal range in group 2, the levels of hs-CRP and IRI were significantly higher than those in group 1, the level of hs-CRP was 2.4 (0.01 - 9.0) mg/L. While FPG and TG were abnormal in group 3, the level of hs-CRP was 2.6 (0.1 - 14.6) mg/L, but the difference had no statistical significance. (3) Pearson correlation analysis showed that there was a moderate correlation between serum hs-CRP and BMI (r = 0.414, P = 0.000). There was a low correlation between hs-CRP and waist circumference, hip circumference and waist to hip ratio (WHR). The correlation of serum hs-CRP with blood pressure, TG, cholesterol, high density lipoprotein-cholesterol (HDL-C), HbA1c, FPG, FINS and Cp had no significant deviation. (4) Multiple linear regression analysis showed that body mass index (BMI) was the only indicator which had correlation with hs-CRP.

CONCLUSION(1) There may be a chronic low-grade inflammation and insulin resistance in obese children. (2) The level of hs-CRP might be independently correlated with BMI in children. (3) Hs-CRP and IRI elevated before FPG and TG did, which may suggest that the low-grade inflammation and insulin resistance may be a pathogenic base of DM rather than the outcome of it. (4) The elevation of hs-CRP may help predict impaired glucose and lipid metabolism.

Adolescent ; Blood Glucose ; analysis ; Body Mass Index ; C-Reactive Protein ; analysis ; Case-Control Studies ; Child ; Female ; Glucose Tolerance Test ; Humans ; Insulin Resistance ; Lipoproteins, HDL ; blood ; Male ; Obesity ; blood ; metabolism ; Triglycerides ; blood ; Waist Circumference ; Waist-Hip Ratio