• Journal of Nutrition and Health
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• v.35 no.10
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• pp.1060-1069
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• 2002

High insulin level is known to be a risk factor of coronary heart disease. High insulin level with normal glycemic control is known to be an indicator for insulin resistance. This study was aimed to find out the influencing factors for the fasting serum insulin levels in elderly females with normal glycemic control. One hundred thirty-eight older females aged over 60 years without diabetes medication and high blood HBA1c level were examined on the serum fasting insulin concentration, anthropometry and asked about nutrient intake and exercise habits. The elderly were categorized into 3 group according to the fasting insulin level. The high insulin group was in a state of hyperinsulinemia. Except vitamin C, the nutrient intakes showed no difference according to fasting serum insulin level. But the intakes of calorie and protein per kg body weight were significantly lower in the high insulin group. The intakes of most nutrients except vitamin B$_1$, C and niacin were lower than the korean RDA in all the insulin group. Especially, the intakes of vitamin B$_1$ and Ca were below 75% of the korean RDA. Weight, BMI, body fat percent, body fat mass and fat-free mass, circumferences of waist and hip, WHR of elderly females were significantly higher in the group with the highest insulin level. The body fat percent in the highest insulin group was 35.8%. showing a state of obesity. The high insulin group showed higher proportion of low exercise frequencies per week and short exercise duration. Therefore, the mean energy expenditure for exercise were lower in this group, showing a state of very low exercise activity. Age and waist circumference in elderly females could explain to the 14.5% variances of the fasting insulin level according to multiple stepwise regression. It can be concluded that aging and central body fat deposition influence independently the serum fasting insulin level in elderly females with normal glucose level.

• Proceedings of the Korean Society of Food Science and Nutrition Conference
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• 2004.11a
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• pp.185-197
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• 2004

Type 2 diabetes is characterized by hyperglycemia and hyperinsulinemia, features of insulin resistance. In vivo treatment of ob/ob mice with hydrolyzed fibroin reverses these pathological attributes (6). To explore the mechanism underlying this effect, we have used the 3T3-Ll adipocytes as a cell type which would represent the periphery, in vivo. Exposure of 3T3-Ll adipocytes to chronic insulin leads to the a 50% loss of insulin-stimulated glucose uptake. Chronic exposure to fibroin blocked, in part, the response to chronic insulin but also increased the sensitivity of control cells to the acute action of insulin. The later effect was most robust at physiological concentrations of insulin. Fibroin did not prevent the insulin-induced down-regulation of the insulin receptor or the tyrosine kinase activity associated with the receptor. Further, fibroin had no affect on the loss in activity of the insulin-sensitive down-stream kinase, Akt. Interestingly, fibroin accelerated glucose metabolism and glycogen turnover independent of insulin action. In addition, fibroin up-regulated GLUT1 which increased its expression at the cell surface and caused the redistribution of GLUT4 to the plasma membrane. Together, these later effects would lead to an improvement in hyperglycemia in vivo which would in turn reduce the need for insulin.

• Animal cells and systems
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• v.13 no.1
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• pp.17-23
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• 2009

In previous studies, we found that Annexin I (Anx I) was co-secreted with insulin in response to glucose, and that extracellular Anx I stimulated the release of insulin via the Anx I binding site in rat pancreatic islets and the &-cell line. However, the role that Anx I plays in the insulin secretion was not established. Therefore, in this study, we evaluated the insulin secretion pattern in response to Anx I and the involvement of the cytoskeleton or PKC in Anx Istimulated insulin secretion in MIN6N8a cells. The peak time of insulin secretion in response to Anx I treatment corresponded with the second phase insulin secretion by glucose in the perifused pseudoislets. In addition, Anx I-stimulated insulin secretion was not affect by readily releasable pool depletion. Taken together, these findings indicate that Anx I treatment was associated with movement of the reserve pool of insulin. Furthermore, Anx I-stimulated insulin secretion was attenuated by treatment with a microfilament inhibitor, cytochalasin B, as well as by PKC down regulation. These results indicate that Anx I may be a regulator of second phase insulin secretion.

• Korean Journal of Veterinary Research
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• v.35 no.4
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• pp.699-712
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• 1995

The present study, to evaluate the effect of vitamin E on the oxidative stress in STZ-treated rat and BB rat, was investigated the biochemical enzyme activity in the serum, and malondialdehyde and carbonyl group in the RBC membrane, liver and microsomal fraction after vitamin E and/ or insulin treatment. Results obtained through the experiments were summarized as follows; 1. Effect of vitamin E and/or insulin treatment in STZ-treated rat 1) Lipid peroxidation level in RBC membrane, liver and microsomal fraction was significantly decreased in vi. tamin E and/or insulin treatment group, and especially more significantly decreased in vitamin E with insulin treated group. 2) Protein oxidation level in RBC membrane, liver and microsomal fraction was significantly decreased in vitamin E and/or insulin treatment group. And it was especially more significantly decreased in RBC membrane and liver of vitamin E with insulin treated group. 3) In the enzyme activity in the serum, the activity of AST and ALT was not altered in all experimental group. The increased ALP activity in STZ-treated group was significantly decreased in insulin treated group and vitamin E with insulin treated group. 4) Decreased level of albumin and creatinine after STZ treatment was significantly increased in vitamin E and/or insulin treated group. 5) Level of glucose, cholesterol and triacylglycerol in serum: Glucose level was not significantly different in vitamin E treated group compared to STZ control group. But it was significantly different in the insulin treated group and vitamin E with insulin treated group compared to STZ control group. The cholesterol content in the serum was significantly increased in STZ control group compared to normal control group. And except low dose vitamin E treatment group, it was significantly decreased in vitamin E and/or insulin treated group compared to STZ control group. The triacylglycerol content in the serum was significantly decreased in STZ control group and increased in high dose vitamin E treated group and vitamin E with insulin treated group. But it was not significantly different in low dose vitamin E treated group and insulin treated group compared to STZ control group. 2. Effect of vitamin E and/or insulin treatment in BB rat 1) Lipid peroxidation level in liver was decreased by vitamin E with insulin treatment compared to insulin treatment. But it was not different in microsomal fractions. 2) Protein oxidation level in liver and microsomal fraction was decreased by vitamin E with insulin treatment compared to insulin treatment only in microsomal fractions. These results suggest that the combination treatment of vitamin E and insulin could prevent the oxidative change of lipid and protein of the RBC membrane, liver and microsomal fraction in STZ-treated rats and BB rats.

• Annals of Laboratory Medicine
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• v.38 no.6
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• pp.530-537
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• 2018

Background: Measurement of insulin and C-peptide concentrations is important for deciding whether insulin treatment is required in diabetic patients. We aimed to investigate the analytical performance of insulin and C-peptide assays using the Lumipulse G1200 system (Fujirebio Inc., Tokyo, Japan). Methods: We examined the precision, linearity, and cross-reactivity of insulin and C-peptide using five insulin analogues and purified proinsulin. A method comparison was conducted between the Lumipulse G1200 and Roche E170 (Roche Diagnostics, Mannheim, Germany) systems in 200 diabetic patients on insulin treatment. Reference intervals for insulin and C-peptide concentrations were determined in 279 healthy individuals. Results: For insulin and C-peptide assays, within-laboratory precision (% CV) was 3.78-4.14 and 2.89-3.35%, respectively. The linearity of the insulin assay in the range of 0-2,778 pmol/L was $R^2=0.9997$, and that of the C-peptide assay in the range of 0-10 nmol/L was $R^2=0.9996$. The correlation coefficient (r) between the Roche E170 and Lumipulse G1200 results was 0.943 (P <0.001) for insulin and 0.996 (P <0.001) for C-peptide. The mean differences in insulin and C-peptide between Lumipulse G1200 and the Roche E170 were 19.4 pmol/L and 0.2 nmol/L, respectively. None of the insulin analogues or proinsulin showed significant cross-reactivity with the Lumipulse G1200. Reference intervals of insulin and C-peptide were 7.64-70.14 pmol/L and 0.17-0.85 nmol/L, respectively. Conclusions: Insulin and C-peptide tests on the Lumipulse G1200 show adequate analytical performance and are expected to be acceptable for use in clinical areas.

• BMB Reports
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• v.39 no.4
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• pp.457-463
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• 2006

Insulin resistance is commonly observed in patients prior to the development of type 2 diabetes and may predict the onset of the disease. We tested the hypothesis that impairment in insulin stimulated glucose-disposal in insulin resistant patients would be reflected in the gene expression profile of skeletal muscle. We performed gene expression profiling on skeletal muscle of insulin resistant and insulin sensitive subjects using microarrays. Microarray analysis of 19,000 genes in skeletal muscle did not display a significant difference between insulin resistant and insulin sensitive muscle. This was confirmed with real-time PCR. Our results suggest that insulin resistance is not reflected by changes in the gene expression profile in skeletal muscle.

• Toxicological Research
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• v.21 no.3
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• pp.195-208
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• 2005

Diabetes is a major cause of morbidity and mortality, and associated with a high risk of atherosclerosis, and liver, kidney, nerve and tissue damage. Defective insulin secretion in pancreas and/or insulin resistance in peripheral tissues is a central component of diabetes. It is well established that, regardless of the degree of muscle insulin resistance, glucose levels in diabetic and non-diabetic individuals are determined by the rate of hepatic glucose production. Moreover recently studies using liver-specific insulin receptor knockout mice show the paramount role of the liver in insulin resistance and diabetes. Insulin exerts a multifaceted and highly integrated series of actions via its intracellular signaling systems. The first major section of this review defines the major insulin-mediated signaling pathways including phosphatidylinositol 3-kinase and mitogen activated protein kinases. The second major section of the review presents a summary and evaluation of methods for determination of the role and function of signaling pathways, including methods for determination of kinase phosphorylation, the use of pharmacological inhibitors of kinase and dominant-negative kinase constructs, and the application of new RNA interference methods.

• Asian-Australasian Journal of Animal Sciences
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• v.10 no.1
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• pp.134-140
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• 1997

Objectives of this study were to determine effects of insulin on acetyl-CoA carboxylase (ACC) activity and correlate this activity with relative amounts of ACC in MAC-T cells. MAC-T cells were grown in Medium 199 supplemented with fetal bovine serum (5%), cortisol ($1{\mu}g/ml$), and insulin ($1{\mu}g/ml$). At confuluence, the cells were transferred to $100mm^2$ culture dishes coated with the extracelluar matrix. After 10 h of incubation, the media were replaced with media without fetal bovine serum and the concentration of insulin was lowered to 5 ng/ml. After 24 h, the media were changed to contain the varying concentrations of insulin and incubations continued for 48 h. The addition of insulin resulted in increases in the specific activity of ACC. The maximal effects of insulin on the ACC activity occurred at concentrations of insulin, 1,000 ng/ml. In contrast, the relative change in lactate dehydrogenase (LDH) activity in response to increasing insulin concentration was minimal as compared to the effects of insulin on ACC. Transblot and enhanced chemiluminescence (ECL) analysis indicated that the increase in ACC activity in MAC-T cells caused by insulin were due to actual increases in amounts of enzyme.

• Journal of Pharmaceutical Investigation
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• v.27 no.3
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• pp.189-198
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• 1997

The purpose of the present study was to investigate the effect of medium chain fatty acid salts, reported as enhancers in insulin nasal absorption, on the rectal absorption of insulin in rats. The serum glucose and remained insulin level in perfusate were measured after rectal recirculation of insulin with or without sod. laurate, sod. caprate and sod. caprylate in situ. The addition of sod. laurate or sod. caprate reduced serum glucose concentration considerably. Sod. caprate (1.0%) showed the greatest promoting effect on the decrement of serum glucose. Eudispert hv hydrogels containing insulin with medium chain fatty acid salts were, thereby, prepared and evaluated. The release rate of insulin from Eudispert hv hydrogels was reduced with an increase in the content of Eudispert hv, and was raised with increasing NaOH concentration. Ten percent Eudispert hv hydrogels were offered for the rectal administration of insulin. The addition of 1.0% sod. caprate reduced serum glucose concentration remarkably after rectal administration of 10% Eudispert hv hydrogels containing insulin. The level of glucose decrement was greater by 30% compared to subcutaneous administration of insulin solution. From the above findings, Eudispert hv hydrogels would be used as useful rectal delivery systems of insulin.

• Journal of Microbiology and Biotechnology
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• v.26 no.10
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• pp.1781-1789
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• 2016

Glargine insulin is a long-acting insulin analog that helps blood glucose maintenance in patients with diabetes. We constructed the pPT-GI vector to express prepeptide glargine insulin when transformed into Escherichia coli JM109. The transformed E. coli cells were cultured by fed-batch fermentation. The final dry cell mass was 18 g/l. The prepeptide glargine insulin was 38.52% of the total protein. It was expressed as an inclusion body and then refolded to recover the biological activity. To convert the prepeptide into glargine insulin, citraconylation and trypsin cleavage were performed. Using citraconylation, the yield of enzymatic conversion for glargine insulin increased by 3.2-fold compared with that without citraconylation. After the enzyme reaction, active glargine insulin was purified by two types of chromatography (ion-exchange chromatography and reverse-phase chromatography). We obtained recombinant human glargine insulin at 98.11% purity and verified that it is equal to the standard of human glargine insulin, based on High-performance liquid chromatography analysis and Matrix-assisted laser desorption/ionization Time-of-Flight Mass Spectrometry. We thus established a production process for high-purity recombinant human glargine insulin and a method to block Arg (B31)-insulin formation. This established process for recombinant human glargine insulin may be a model process for the production of other human insulin analogs.