PURPOSE: Recent studies demonstrated disruption of the circadian clock gene is associated with the development of obesity and metabolic syndrome. Obesity is often caused by the high calorie intake, In addition, the chronic stress tends to contribute to the increased risk for obesity. To evaluate the molecular mechanisms, we examined the expression of circadian clock genes in high fat diet-induced mice models with the chronic stress. METHODS: C57BL/6J mice were fed with a 45% or 60% high fat diet for 8 weeks. Daily immobilization stress was applied to mice fed with a 45% high fat for 16 weeks. We compared body weight, food consumption, hormone levels and metabolic variables in blood. mRNA expression levels of metabolic and circadian clock genes in both fat and liver were determined by quantitative RT-PCR. RESULTS: The higher fat content induced more severe hyperglycemia, hyperlipidemia and hyperinsulinemia, and these results correlated with their relevant gene expressions in fat and liver tissues. Chronic stress had only minimal effects on metabolic variables, but it altered the expression patterns of metabolic and circadian clock genes. These results suggest that the fat metabolism regulates the function of the circadian clock genes in peripheral tissues, and stress hormones may contribute to its regulation.
Animals ; Body Weight ; Circadian Clocks* ; Diet, High-Fat ; Gene Expression* ; Hyperglycemia ; Hyperinsulinism ; Hyperlipidemias ; Immobilization ; Liver ; Metabolism ; Mice ; Obesity ; RNA, Messenger

BACKGROUND/OBJECTIVES: The goal of this study was to examine the effect of Sargassum coreanum extract (SCE) on blood glucose concentration and insulin resistance in C57BL-KsJ-db/db mice. MATERIALS/METHODS: For 6 weeks, male C57BL/KsJ-db/db mice were administrated SCE (0.5%, w/w), and rosiglitazone (0.005%, w/w). RESULTS: A supplement of the SCE for 6 weeks induced a significant reduction in blood glucose and glycosylated hemoglobin concentrations, and it improved hyperinsulinemia compared to the diabetic control db/db mice. The glucokinase activity in the hepatic glucose metabolism increased in the SCE-supplemented db/db mice, while phosphoenolpyruvate carboxykinase and glucose-6-phosphatase activities in the SCE-supplemented db/db mice were significantly lower than those in the diabetic control db/db mice. The homeostatic index of insulin resistance was lower in the SCE-supplemented db/db mice than in the diabetic control db/db mice. CONCLUSIONS: These results suggest that a supplement of the SCE lowers the blood glucose concentration by altering the hepatic glucose metabolic enzyme activities and improves insulin resistance.
Animals ; Blood Glucose ; Glucokinase ; Glucose ; Glucose-6-Phosphatase ; Hemoglobin A, Glycosylated ; Humans ; Hyperglycemia* ; Hyperinsulinism ; Insulin Resistance* ; Insulin* ; Male ; Metabolism ; Mice* ; Phosphoenolpyruvate ; Sargassum*

OBJECTIVETo investigate the changes of CD4 + CD25 + Foxp3 + regulatory T cells in the peripheral blood mononuclear cells (PBMC) and their association with insulin resistance in different stages of prostate cancer (PCa).

METHODSUsing flow cytometry, we counted the CD4+ CD25 + Foxp3 + regulatory T cells in the PBMCs of 62 PCa patients (5 cases of TNM stage I, 16 cases of stage II, 21 cases of stage III, and 20 cases of stage IV) and 42 normal healthy controls, and calculated their proportion in the CD4+ T-lymphocytes. We determined the levels of fast blood glucose (FBG) and fast insulin (FINS) for the insulin resistance index (HOMA-IR), obtained the serum IGF-1 level by ELISA, and analyzed the relationship of the count and proportion of CD4+ CD25+ Foxp3+ regulatory T cells with insulin resistance by comparison between the PCa patients and normal healthy controls.

RESULTSCompared with the control group, the PCa patients showed significantly increased HOMA-IR (3.68 ± 1.42 vs 6.68 ± 1.66), decreased level of serum IGF-1 ([164.56 ± 30.58] vs [96.39 ± 21.21] ng/ml), and elevated count ([1.99 ± 0.78 ] x 10(7) vs [3.55 ± 0.29] x 10(7)) and proportion ([5.33 ± 0.65] vs [13.88 ± 0.96]%) of CD4 + CD25 + Foxp3 regulatory T cells in the PBMCs. The TNM stage was correlated positively with the count and percentage of CD4 + CD25+ Foxp3 + regulatory T cells and HOMA-IR, but negatively with the level of serum IGF-1. Meanwhile, the count and percentage of CD4 + CD25 + Foxp3 + regulatory T cells were found to have a positive correlation with HOMA-IR (r = 0.722 and 0.689, P < 0.01) but a negative correlation with the level of serum IGF-1 (r = -0.747 and -0.896, P < 0.01).

CONCLUSIONThe count and proportion of CD4+ CD25 + Foxp3 + regulatory T cells in the peripheral blood and insulin resistance increase with the elevated stage of PCa. CD4 + CD25 + Foxp3 + regulatory T cells may be involved in the occurrence and progression of PCa by regulating insulin resistance.

Aged ; CD8-Positive T-Lymphocytes ; Case-Control Studies ; Disease Progression ; Enzyme-Linked Immunosorbent Assay ; Flow Cytometry ; Humans ; Hyperinsulinism ; Insulin ; blood ; Insulin Resistance ; Insulin-Like Growth Factor I ; metabolism ; Leukocytes, Mononuclear ; Lymphocyte Count ; Male ; Prostatic Neoplasms ; blood ; immunology ; pathology ; T-Lymphocytes, Regulatory

To explore the effects of serum insulin on the expression of ChREBP, ACC and FAS in vivo, KKAy mice which were characterized with high levels of both serum insulin and glucose and DIO mice which were characterized with high serum insulin level alone were utilized, separately. The age-matched C57BL/6J mice fed with standard chow were used as normal control (Con). Expressions of hepatic ChREBP, ACC and FAS were detected by Western blotting. As the results, in KKAy mice, a positive correlation between the levels of serum insulin and glucose (r = 0.902, P < 0.000), as well as between the levels of serum insulin and TG (r = 0.732, P < 0.000), was observed. Meanwhile, the expressions of hepatic ChREBP, ACC and FAS increased significantly and accompanied with its hyperinsulinemia and hyperglycemia, separately. In DIO mice, correlation between the levels of serum insulin and TG (r = 0.722, P < 0.001) also showed positive, and the expressions of hepatic ChREBP, ACC and FAS increased significantly and also accompanied with its hyperinsulinemia. However, their blood glucose values were almost normal. These demonstrated that hyperinsulinemia may cause glycolipid metabolic disorders by up-regulating the expression of ChREBP in vivo.
Animals ; Blood Glucose ; metabolism ; Hyperglycemia ; metabolism ; Hyperinsulinism ; metabolism ; Insulin ; blood ; Liver ; metabolism ; Mice ; Mice, Inbred C57BL ; Nuclear Proteins ; metabolism ; Transcription Factors ; metabolism

Betaine supplementation has been shown to alleviate altered glucose and lipid metabolism in mice fed a high-fat diet or a high-sucrose diet. We investigated the beneficial effects of betaine in diabetic db/db mice. Alleviation of endoplasmic reticulum (ER) and oxidative stress was also examined in the livers and brains of db/db mice fed a betaine-supplemented diet. Male C57BL/KsJ-db/db mice were fed with or without 1% betaine for 5 wk (referred to as the db/db-betaine group and the db/db group, respectively). Lean non-diabetic db/+ mice were used as the control group. Betaine supplementation significantly alleviated hyperinsulinemia in db/db mice. Betaine reduced hepatic expression of peroxisome proliferator-activated receptor gamma coactivator 1 alpha, a major transcription factor involved in gluconeogenesis. Lower serum triglyceride concentrations were also observed in the db/db-betaine group compared to the db/db group. Betaine supplementation induced hepatic peroxisome proliferator-activated receptor alpha and carnitine palmitoyltransferase 1a mRNA levels, and reduced acetyl-CoA carboxylase activity. Mice fed a betaine-supplemented diet had increased total glutathione concentrations and catalase activity, and reduced lipid peroxidation levels in the liver. Furthermore, betaine also reduced ER stress in liver and brain. c-Jun N-terminal kinase activity and tau hyperphosphorylation levels were lower in db/db mice fed a betaine-supplemented diet, compared to db/db mice. Our findings suggest that betaine improves hyperlipidemia and tau hyperphosphorylation in db/db mice with insulin resistance by alleviating ER and oxidative stress.
Acetyl-CoA Carboxylase ; Animals ; Betaine ; Brain ; Carnitine O-Palmitoyltransferase ; Catalase ; Diet ; Diet, High-Fat ; Endoplasmic Reticulum ; Gluconeogenesis ; Glucose ; Glutathione ; Humans ; Hyperinsulinism ; Hyperlipidemias ; Insulin Resistance ; JNK Mitogen-Activated Protein Kinases ; Lipid Metabolism ; Lipid Peroxidation ; Liver ; Male ; Mice ; Oxidative Stress ; PPAR alpha ; PPAR gamma ; RNA, Messenger ; Transcription Factors

OBJECTIVE: To evaluate the change of plasma level of retinol binding protein 4 (RBP4) in patients with coronary heart disease, and to explore the effect of hyperinsulinemia. METHODS: This study was carried out at Xiangya Hospital of Central South University, China, from September 2009 to May 2010. Thirty patients with coronary artery disease (the CAD group) were confirmed by coronary angiography, 29 patients with CAD plus hyperinsulinemia (the CAD+HIns group), and 30 healthy subjects were enrolled as controls (the control group). The peripheral blood sample from the anticubital vein was collected aseptically in all the subjects to measure the RBP4 by enzyme linked immunosorbent-assay (ELISA). The height, weight, body mass index (BMI) the waist-to-hip ratio (WHR), the blood pressure, the fasting plasma glucose (FPG), the fasting insulin (Fins), the 2-hour postprandial inslulin (2hPIns), and the homeostasis model assessment-insulin resistance index (HOMA-IR) was measured. The lipids, high sensitivity C reactive protein (hsCRP), uric acid(UA), free fatty acids (FFA) were all examined. RESULTS: The level of plasma RBP4 in the CAD+HIns group was higher than that in the CAD group and the control group (both P<0.01), with no significant difference of plasma RBP4 between the CAD group and the control group (P>0.05). Correlation analysis showed that the plasma RBP4 level was significantly correlated with BMI, FPG, FIns, 2hPIns, HOMA-IR, TG, HDL-C, UA, and hsCRP (r=0.259, 0.331, 0.582, 0.452, 0.600, 0.236, -0.290, 0.243, 0.231, respectively; all P>0.05). Multiple regression analysis showed that BMI, 2hPIns, and HOMA-IR were the independent factors related to RBP4. CONCLUSION The plasma level of RBP4 does not increase in the CAD group, but it is high in the CAD +HIns group. RBP4 level is related to BMI, lipids, UA, and other cardiovascular risk factors. BMI, 2hPIns, and HOMA-IR are the independent factors associated with RBP4.
Adult ; Aged ; Case-Control Studies ; Coronary Disease ; blood ; complications ; Female ; Humans ; Hyperinsulinism ; blood ; complications ; Insulin Resistance ; physiology ; Lipids ; blood ; Male ; Middle Aged ; Retinol-Binding Proteins, Plasma ; analysis ; metabolism ; Uric Acid ; blood

The Otsuka Long-Evans Tokushima Fatty (OLETF) rat, a model of spontaneous type 2 diabetes (T2D), develops hyperglycemic obesity with hyperinsulinemia and insulin resistance after the age of 25 weeks, similar to patients with noninsulin-dependent diabetes mellitus (DM). In the present study, we determined whether there are differences in the pattern of gene expression related to glucose and lipid metabolism between OLETF rats and their control counterparts, Long-Evans Tokushima (LETO) rats. The experiment was done using 35-week-old OLETF and LETO rats. At week 35 male OLETF rats showed overt T2D and increases in blood glucose, plasma insulin, plasma triglycerides (TG) and plasma total cholesterol (TC). Livers of diabetic OLETF and LETO rats also showed differences in expression of mRNA for glucose and lipid metabolism related genes. Among glucose metabolism related genes, GAPDH mRNA was significantly higher and FBPase and G6Pase mRNA were significantly lower in OLETF rats. For lipid metabolism related genes, HMGCR, SCD1 and HL mRNA were substantially higher in OLETF rats. These results indicate that gluconeogenesis in OLETF rats is lower and glycolysis is higher, which means that glucose metabolism might be compensated for by a lowering of the blood glucose level. However, lipid synthesis is increased in OLETF rats so diabetes may be aggravated. These differences between OLETF and LETO rats suggest mechanisms that could be targeted during the development of therapeutic agents for diabetes.
Animals ; Blood Glucose ; Cholesterol ; Diabetes Mellitus, Type 2 ; Gene Expression ; Gluconeogenesis ; Glucose ; Glycolysis ; Humans ; Hyperinsulinism ; Insulin ; Insulin Resistance ; Lipid Metabolism ; Liver ; Male ; Obesity ; Plasma ; Rats ; Rats, Inbred OLETF ; RNA, Messenger ; Triglycerides

Leptin, the product of the adipose-specific ob gene, regulates food intake and energy expenditure in animal models. It is well known that serum leptin levels are increased in patients with chronic renal failure before start of dialysis or even after dialysis. This disorder is basically mediated by a decrease in the renal clearance of leptin, whereas the potential role of an increased secretion of this hormone awaits further confirmation. In this issue of the Journal, Park and Do investigate the longitudinal changes in body composition, serum(S) and dialysate(D) leptin levels in CAPD patients with time. There are significant increases in fat mass, S and D leptin at the 12th month after initiation of PD, especially in diabetes. Factors associated with the changes of fat mass during the first 1 year are D/Plasma 4-hour creatinine, glucose absorption via peritoneal cavity, and duration of dialysis. The correlation between changes of S or D leptin and %fat mass is significant. Consequently, they conclude that increased leptin levels of serum and dialysate may be associated with fat mass in PD patients with time. They found much further increase of D leptin concentration than S leptin, suggesting the possibility of intraperitoneal production of leptin. The molecular weight of leptin is small enough to pass through the peritoneum. Therefore, the extent of S leptin cleared by PD and/or whether a significant intraperitoneal leptin production occurs during PD with glucose-rich solution should be studied. It is well documented that the continuous glucose load during PD will result in chronic hyperinsulinemia which has been shown to increase leptin level by about 40%. Increased generation of proinflammatory cytokines, which is a common feature of PD, may also be a factor stimulating leptin gene expression. The relationship between insulin or proinflammatory cytokine and leptin concentration in PD patients is worthy of further study. In addition, the finding that the dialysate concentration of vascular endothelial growth factor potentially mediating neovascularization in the peritoneal cavity positively correlate with the increase of D/S leptin during the 1st year deserve consideration.
Absorption ; Body Composition ; Creatinine ; Cytokines ; Dialysis ; Eating ; Energy Metabolism ; Gene Expression ; Glucose ; Humans ; Hyperinsulinism ; Insulin ; Kidney Failure, Chronic ; Leptin* ; Models, Animal ; Molecular Weight ; Negotiating ; Peritoneal Cavity ; Peritoneal Dialysis ; Peritoneal Dialysis, Continuous Ambulatory* ; Peritoneum ; Vascular Endothelial Growth Factor A

OBJECTIVETo explore the relationship between serum level of leptin and the components of metabolic syndrome in a group of mid-aged Chinese population.

METHODS345 adults (184 men and 161 women) aged 46 - 53 were enrolled from Fetal Origin of Adult Disease (FOAD) cohort to participate the clinic examination including anthropometry, measurements of blood pressure, fasting and 2 hr plasma levels of glucose and insulin, serum levels of lipid and leptin. HOMA-IR index was calculated to estimate individual insulin resistance. Metabolic syndrome (MS) was diagnosed according to the definition criteria issued by the International Diabetes Federation (IDF) in 2005.

RESULTSThe prevalences of central obesity, higher serum level of triglyceride (TG), lower serum level of high-density lipoprotein (HDL-C), IFG, higher blood pressure and MS were 53.0%, 47.5%, 34.2%, 26.7%, 33.9%, 31.9% in this mid-aged population, respectively. Serum geometric mean level of leptin was higher in females than in males. Serum level of leptin increased with the prevalence of MS and components of abnormal metabolism. The serum level of leptin compared with central obesity, higher blood pressure, higher serum level of triglyceride (TG), lower serum level of high-density lipoprotein cholesterol (HDL-C), IFG and MS was significantly higher respectively (P < 0.05) without HDL-C in males. The serum level of leptin increased with the number of components of abnormal metabolism subjects had (P < 0.001).

CONCLUSIONThe serum level of leptin in this population is significantly associated with MS and components of MS. Hyperleptinemia could be a new component of metabolic syndrome. It might be a target in selection of MS and relative diseases.

China ; epidemiology ; Cholesterol, HDL ; blood ; Cohort Studies ; Female ; Humans ; Hyperinsulinism ; blood ; Insulin ; metabolism ; Insulin Resistance ; Leptin ; blood ; Male ; Metabolic Syndrome ; blood ; epidemiology ; Middle Aged ; Obesity ; blood

OBJECTIVETo investigate the role and mechanism of c-Jun N-terminal kinase (JNk) inhibitor (SP600125) in amelioration of insulin resistance after scald.

METHODSTwenty-four Sprague-Dawley rats were randomized into sham (the process of scald was mimicked by water at room temperature) , scald, scald and SP600125 groups. The rats were inflicted with 30% TBSA full-thickness scald in the latter two groups. Euglycemic-hyperinsulinemic glucose clamp experiment was carried out 4 days after scald. SP600125 was administered to the rats in scald and SP600125 2 hrs before Euglycemic-hyperinsulinemic glucose clamp was performed. Changes in the phospho-Serine307 and phospho-tyrosine of IRS-1 activity, as well as expression of phospho-JNK in muscles were determined.

RESULTSEuglycemic-Hyperinsulinemic Glucose Clamps experiment showed that the infusion rate of 100 g/L glucose in sham, scald, scald and SP600125 groups were (12. 33 +/-0. 42) , (6. 61 +/-0. 27) , (11. 11 +/-0. 68) mgx kg(-1) x min(-1) , respectively ( P <0.01). The level of IRS-1 Serine307 phosphorylation and JNK activity in muscles were significantly increased, while insulin-induced tyrosine phosphorylation of IRS-1 decreased markedly after scald. Compared with scald group, the level of IRS-1 Serine307 phosphorylation and JNK activity in scald and SP600125 group were decreased but tyrosine phosphorylation was elevated.

CONCLUSIONSP600125 can partially ameliorate insulin resistance after scald by inhibition of JNK activation, and decrease the level of IRS-1 phospho-serine307.

Animals ; Anthracenes ; pharmacology ; Burns ; complications ; metabolism ; Hyperinsulinism ; etiology ; Insulin ; metabolism ; Insulin Receptor Substrate Proteins ; metabolism ; Insulin Resistance ; JNK Mitogen-Activated Protein Kinases ; antagonists & inhibitors ; Phosphorylation ; Protein Kinase Inhibitors ; pharmacology ; Rats ; Rats, Sprague-Dawley