ABSTRACT
After the stratification of the normal glucose tolerance, the changes of insulin resistance and βcell function in the development of type 2 diabetes mellitus were investigated. A retrospective analysis on data of 275 cases with oral glucose insulin releasing tests. The area under the insulin curve (AUCINS ) 108. 43 mU/ L was taken as the critical value of diagnosis. Normal glucose tolerance subjects were divided into the NGT-a group(AUCINS<108. 43 mU/ L) and the NGT-b group(AUCINS≥108. 43 mU/ L). The plasma glucose, insulin, insulin sensitivity, and β cell function were compared among the 4 groups: NGT-a group (n=96), NGT-b group (n=49), prediabetes group (n=71), and type 2 diabetes mellitus group ( n = 59). Among the fasting insulin, 2 h insulin, AUCINS , early-phase insulin secretion index(△I30 / △G30), the ratio of total insulin area under curve, and total glucose area under curve, disposition index, homeostasis model assessment for insulin resistance, and Matsuda insulin sensitivity index, the relationship as follows: NGT-b group>prediabetes group>NGT-a group>type 2 diabetes mellitus group. The NGT-b group was always the highest, prediabetes group was lower, NGT-a group and type 2 diabetes mellitus group were the lowest, there were significant differences (all P<0. 05). Making the NGT-a group as the basic state, in the NGT-b group, β cell function has begun to appear compensation and insulin resistance, and β cell function compensation reached the peak, the β cell function in the prediabetes group was beginning to compensate for the deficiency, the function of β cell in type 2 diabetes mellitus group decreased further. These findings suggest that the development process of type 2 diabetes mellitus could be the following four stages according to the function of β cell: β cell function normal, β cell functional compensation, β cell function loss of compensation, and finally β cell function failure.
ABSTRACT
After the stratification of the normal glucose tolerance, the changes of insulin resistance and βcell function in the development of type 2 diabetes mellitus were investigated. A retrospective analysis on data of 275 cases with oral glucose insulin releasing tests. The area under the insulin curve (AUCINS ) 108. 43 mU/ L was taken as the critical value of diagnosis. Normal glucose tolerance subjects were divided into the NGT-a group(AUCINS<108. 43 mU/ L) and the NGT-b group(AUCINS≥108. 43 mU/ L). The plasma glucose, insulin, insulin sensitivity, and β cell function were compared among the 4 groups: NGT-a group (n=96), NGT-b group (n=49), prediabetes group (n=71), and type 2 diabetes mellitus group ( n = 59). Among the fasting insulin, 2 h insulin, AUCINS , early-phase insulin secretion index(△I30 / △G30), the ratio of total insulin area under curve, and total glucose area under curve, disposition index, homeostasis model assessment for insulin resistance, and Matsuda insulin sensitivity index, the relationship as follows: NGT-b group>prediabetes group>NGT-a group>type 2 diabetes mellitus group. The NGT-b group was always the highest, prediabetes group was lower, NGT-a group and type 2 diabetes mellitus group were the lowest, there were significant differences (all P<0. 05). Making the NGT-a group as the basic state, in the NGT-b group, β cell function has begun to appear compensation and insulin resistance, and β cell function compensation reached the peak, the β cell function in the prediabetes group was beginning to compensate for the deficiency, the function of β cell in type 2 diabetes mellitus group decreased further. These findings suggest that the development process of type 2 diabetes mellitus could be the following four stages according to the function of β cell: β cell function normal, β cell functional compensation, β cell function loss of compensation, and finally β cell function failure.
ABSTRACT
Objective To explore more suitable calculation method of the insulin dosage in insulin hypoglycemia-growth hormone stimulation test(insulin tolerance test, ITT). Methods Fifty-six subjects suspected of growth hormone deficiency were divided into primary and secondary onset groups. All the patients took oral glucose tolerance test and ITT. Homeostasis model of assessment for insulin resistance index ( HOMA-IR) and insulin sensitivity index ( ISI), area under insulin curve ( AUCINS ) and the area under glucose curve ( AUCPG ) were calculated. The insulin dosages during ITT between two groups were compared and the main factors influencing the insulin dosage were analyzed. Results There was no difference in the insulin dosage during ITT between primary and secondary groups. The actual dosage of insulin in this cohort study revealed a significant difference from the initial insulin dosage recommended by the guideline. Multiple linear regression analysis found that AUCINS and body mass index were the independent factors affecting the insulin dosage. Then the optimized coefficient of ITT ( γ) were found. Conclusion The insulin dosage used in our study was inconsistent with the guidelines-recommended ones. In order to make ITT more efficient and safer, a more optimized calculation method to improve the successful rate of insulin-induced hypoglycemia in ITT is proposed.
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Objective To investigate clinical value of arginine stimulation test to estimate the first-phase insulin release of pancreatic isletβ-cell and evaluation indicators of insulin release.Methods Choose inpatients with diabetes in the department of endocrinology,divide into type 1 diabetes mellitus group (T1DM group)12 cases,type 2 diabetes mellitus group a (T2DMa group,duration of no more than 1 year)57 cases and type 2 diabetes mellitus group b (T2DMb group,more than 1 year),82 cases.Theserum levels of blood glucose (PG),insulin (INS)and C-peptide (CP)were determined at fasting 0 mi-nutes and 2,4,6 minutes after arginine stimulation,and process the results statistically.Results After arginine stimulation, three groups of PG and the T1DM group of INS and CP had no obvious change and there were no statistical significance (F=0.150~0.696,P>0.05).In T2DMa group and T2DMb group,the peak level of INS and CP appeared at 2nd minute,and those in T2DMa group were higher than those in T2DMb group and these were statistical significance (F=12.145~40.518,P0.05).In T2DMa and T2DMb groups,those had positive correlation (r=0.768, 0.722,P<0.01).Conclusion Arginine stimulation test can be sensitively estimated the first-phase insulin release of pancre-atic isletβ-cell and that has certain clinical application value.△INS and △CP can be used to evaluating insulin release.
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Objective To investigate the release pattern of insulin after the load of glucose in patients with polycystic ovary syndrome ( PCOS ) and normal oral glucose tolerance.Methods Sixty-three patients with PCOS were undertaken oral glucose tolerance test (OGTT) and insulin release test,while 34 women with normal menstrual cycle served as control.Results Among 63 patients with PCOS,33 cases were obese with body mass index over 25 kg/m2,including 5 with abnormal OGTT.All 30 non-obese patients with PCOS had normal OGTT.The prevalences of insulin resistance were 78.8％,16.7％,and 9.0％ in obese PCOS,non-obese PCOS,and control groups,respectively.Abnormal insulin release curve were found in 84.5％,70.0％,and 14.7％ of subjects in these 3 groups,respectively.In 58 PCOS patients with normal OGTT,the prevalence of insulin resistance was 44.8％,and 75.9％with abnormal insulin release curve. Among them,body mass index of 32 patients,whose homeostasis model assessment for insulin resistance (HOMA-IR) and fasting insulin remained in normal range,was similar to those of control group [ ( 20.52 ± 2.86 vs 20.01 ± 2.54 ) kg/m2,P＞0.05].Conclusion These findings indicate that insulin release test is useful in detecting insulin resistance.Insulin release is elevated in PCOS patients even with normal OGTT.
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Objective To investigate the effect of HIV-1 protease inhibitor saquinavir on insulin signaling and β-cell function in rat INS-1 cells. Methods INS-1 cells were preincubated with 0 or 10 μmol/L saquinavir for 48 h, stimulated with 100 nmol/L insulin for 2 min or 20 mmol/L glucose for 30 min. Insulin signaling parameters were analyzed by immunoprecipitation and Western blot on cell lysates. Insulin concentrations in the supernatant were measured by ELISA, and standardized by cellular DNA contents. Cell count with trypan blue stain and MTT test were determined to evaluate the effect of saquinavir on cell viability. Results Treatment with saquinavir for 48 h significantly decreased insulin-stimulated phosphorylation of IRS-1, IRS-2 and Thr~(308)-phosphorylation of Akt in INS-1 cells by 60%, 66% and 55%, decreased the rate of basal insulin secretion and glucose-stimulated insulin release by 39% and 49% compared with control cells, respectively. Conclusions Treatment with saquinavir impairs insulin signal transmission in pancreatic β cells and results in insulin resistance in β cells. This effect might influence the function of β cells.
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Objective To study on the of insulin secretion relations to plasma glucose and the effect of different plasma glucose levels on insulin secretion stimulated by glucose.Methods 98 patients with type 2 diabetes were undergone 75g orally glucose tolerance test(OGTT) and insulin releasing test(IRT) 48hours after stopping administration of oral hypoglycemia agent.The data of plasma levels of glucose and insulin,and the time of peak glucose and insulin and postprandial plasma gluocse and insulin ,the time of peak glucose value,the ratio of maximal glucose to base glucose on base and stimulated insulin secrtion were analyzed statistically.Results The findings demonstrated that plasma glucose of OGTT has relation to base insulin level wihle no significance ,but to stimulate insulin (I max ) of IRT and the ratio of maximal insulin to base insulin(M/B 1).I max and M/B 1 when base glucose level excess 11 1mmol/L were one third of the same index when base glucose level less than 11 1mmol/L(P