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This study assessed the effects of leukemia-related protein 16 (LRP16) on the regulation of pancreatic functions in mouse insulinoma (MIN6) cells. Cells with down-regulated expression of LRP16 were obtained by a shRNA interference strategy. Insulin content and glucose-stimulated insulin secretion (GSIS) were examined by radioimmunoassay. Western blotting was applied to detect protein expression. Glucose-stimulated sub-cellular localization of PDX-1 was immunocytochemically determined. Cell proliferation and apoptosis were detected by flow cytometry. Our results showed that LRP16 regulated insulin content in MIN6 cells by controlling expression of insulin and insulin transcription factors. LRP16 gene silence in MIN6 cells led to reduced cell proliferation and increased apoptosis. The observation of phosphorylation of serine-473 Akt and the localization of PDX-1 to the nucleus under glucose-stimulation exhibited that LRP16 was a component mediating Akt signaling in MIN6 cells. These results suggest that LRP16 plays a key role in maintaining pancreatic β-cell functions and may help us to understand the protective effects of estrogen on the functions of pancreatic β-cells.
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Objective To compare the difference of cutpoint and clinical significance of HbA1C for the diagnosis of abnormal glucose metabolism in two population groups with different ages.Methods According to oral glucose tolerance test(OGTT),the cutpoint and clinical significance of HbA1C for the diagnosis of type 2 diabetes and impaired glucose regulation(IGR)were investigated in the two population groups.Results The mean HbA1C of 1 064 young subjects in an academy and 1 671 aged subjects in a community were 5.31% ±0.41% and 5.79% ±0.71%,respectively.The cutpoints of HbA1C for diagnosis of diabetes were 5.7%(specificity 86.7%,sensitivity 66.7%)and 5.9%(specificity 73.8%,sensitivity 80.1%)in the two population groups,and 5.6% for diagnosis of IGR (specificity 82.8%,sensitivity 55.8%)and 5.7%(specificity 60.9%,sensitivity 64.3%),respectively.87.8%,78.7%,and 38.5% were diagnosed diabetes by current OGTT criteria at HbA1C levels of ≥5.7%,≥5.9%,and≥6.5%,IGR being 61.6%,39.6%,and 4.1%,and normal glucose tolerance being 24.4%,10.0%,and 0.4%.Conclusion The cutpoints of HbA1C for diagnosis of diabetes and IGR are different in populations with different ages and HbA1C levels.As one of diagnostic criteria for diabetes,HbA1C 6.5% with relatively higher specificity and lower sensitivity must be combined with fasting blood glucose,random blood glucose,and OGTT.
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Objective To study the effect of the polymorphism of (AC) n of aldose reductase (AR) gene on the erythrocyte AR activity in type 2 diabetes mellitus (DM). Methods One hundred and sixty three cases of type 2 DM and forty two controls were included in this study. The subjects were devided into DM without diabetic microangiopathy (DMAP) (NDC) (66 cases), DMAP groups (97 cases), and normal controls (CON) (42 cases); further, according to the type of allele, the subjects were devided into DM with Z+2 (DZ+2) (54 cases), DM with Z-2 (DZ-2) (35 cases), DM with both Z+2 and Z-2 (Z+2/Z-2) (18 cases), DM with neither Z+2 nor Z-2 (X/X) (56 cases), non DM with Z+2 (NZ+2) group (21 cases) and non DM with Z-2 (NZ-2) groups (7 cases). AR activity (ARA) was measured by modified Sriratava method. The differences of ARA were compared among these groups. Results ARA in DMAP group was significantly higher than that in NDC group, ARA in NDC group was significantly higher than that in CON group. Among DZ-2, DZ+2, Z+2/Z-2 and X/X groups, ARA was the highest in DZ-2 group and the lowest in DZ+2 group. ARAs in DZ-2 and NZ-2 groups were significantly higher than those in DZ+2 and NZ+2 groups respectively. In DZ-2 and DZ+2 groups ARA was significantly higher than that in NZ-2 and NZ+2 groups respectively. Conclusion The activation of AR plays an important role in the development of DMAP. Z-2 allele may be an activator and Z+2 allele may be an inhititor of AR.
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Diabetic KK-Ay mice were given glimepiride (GM) and glibenclamide (GB). After treatment, the visceral white fat content, insulin and hypothalamic neuropeptide Y (NPY) levels were significantly lower in GM group than those in GB group, suggesting that in addition to the lower insulin level stimulated by GM, the lower concentration of hypothalamic NPY seems to play a role in lessening increase in body fat of type 2 diabetic animals treated with GM.