| Objective:To study the changes of proinsulin(PI),true insulin(TI) in Graves' disease(GD) with different levels of glucose tolerance and relationship of them to immunoreactive insulin; to study the changes of islet p-cell function.Methods:75g oral glucose tolerance test (OGTT) was performed on controls (n=27) and patients with newly diagnosed Graves' disease (GD) (n=85). Fasting glucose and 0.5h, Ih, 2h, 3h blood glucose after oral glucose were measured. TI and PI were measured in fasting and 2h post oral glucose serum by respective radioimmunoassay kits. IRI was measured routinely. Insulin sensitive index (ISI) and Homa insulin resistance index (Homa-IR) was calculated respectively with TI and IRI. FT3, FT4, s-TSH, TPOAb were measured by immunochemiluminometric assay in fasting serum routinely.Results:1.Either in fasting or in 2h serum, the PI levels were higher in GD patients than those in controls (P<0.05). In GD patients, the PI levels increased stepwisely with blood glucose level rising.2.Fasting TI (FTI) levels were higher in GD patients than those in controls (P<0.05), but there was no difference withinGD patients (p>0.05); those patients with impaired glucose tolerance/impaired fasting glucose (IGT/IFG) had the highest 2h TI concentrations, the 2h TI concentrations of diabetes mellitus(DM) declined to the levels of controls(P>0.05).3.The changes of IRI levels: Fasting IRI levels were higher in GD patients than those in controls (P<0.05), but there was no difference within GD patients (P>0.05); those patients with IGT/IFG had the highest 2h IRI concentrations, the 2h IRI concentrations of DM declined to the levels of controls (P>0.05).4. Fasting PI/IRI and 2h PI/IRI were both higher in GD patients than those in the controls (P<0.05). In GD patients, Group DM had the highest ratio (P<0.05), the ratio was 33.10% and 26.45%, but that in control group was 9.63% and 8.68%.5.As for TI/IRI, fasting and 2h TI/IRI ratio in controls were higher than those in GD patients (.PO.05). In GD patients, there was a declining tendency with blood glucose rising, but it didn't reach statistical significance (P>0.05).6.1nsulin sensitive index 1 (ISI1 )(calculated with TI) and insulin sensitive index 2(ISI2)(calculated with IRI) in GD patients were both lower than those in controls (P<0.05). In GD patients, the two indexes declined with blood glucose rising.7.Homa-IRl (calculated with TI) and Homa-IR2 (calculated with IRI) were both lower in controls and patientswith normal glucose tolerance (NOT) than others (PO.05). There was no difference between Homa-IR2 in IGT/IFG and that in DM, but Homa-IRl of DM was higher than that of IGT/IFG (PO.05).8.Correlation analysis indicated that: 8.1 PI levels had high correlation with thyroid function. Fasting PI (FPI) and OGTT 2hPI both had positive correlation with FT4, the coefficient r were 0.58(P<0.01) and 0.42(P<0.01), but there were highly negative correlation with s-TSH, r were -0.66(P<0.01) and -0.47(P<0.01). PI levels also had correlation with blood glucose (BG). r between FPI and FBG was o.38(P<0.01),2hPI and 2h BG was 0.42(P<0.01).8.2 Both ISI1 and ISI2 had negative correlation with FT4, r were -0.30CPO.01) and -0.42(PO.01); positive correlation with s-TSH, r were 0.31(P<0.01) and 0.39(P<0.01).They both had negative correlation with FPI, r were -0.53(PO.01)and -0.62(P<0.01)8.3 Homa-IRl and Homa-IR2 had correlation with thyroid function also. They had positive correlation with FT4, r were 0.315CPO.01) and 0.391(PO.01); negative correlation with s-TSH, r were -0.30(PO.01) and -0.35(PO.01). They had positive correlation with FPI, r were 0.51(PO.01) and 0.58CPO.01).Conclusion:l.GD patients often had some degree of abnormal glucose metabolism. 2.There was important clinical significance to determine PI and TI in GD patients, especiallyto study islet 3-cell function. PI and TI levels had high correlation with abnormal glucose metabolism. 3. There was islet p-cell dysfunction in GD patients and it became worse and... |
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