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AIM:To explore the effect of diabetic duration and bloodglucose level on insulin like growth factor 1 (IGF-1) geneexpression and serum IGF-1 level.METHODS:Diabetes was induced into Sprague Dawley ratsby alloxan and then the rats were subdivided into differentgroups with varying blood glucose level and diabetic duration.The parameters were measured as follows:IGF-1 mRNA byreverse transcriptase- polymerase chain reaction (RT-PCR),IGF-1 peptide and serum IGF-1 concentration by enzyme-linked immunosorbent assay (ELISA).RESULTS:During early diabetic stage (week 2),incomparison with normal control group (NC),IGF-1 mRNA(1.17±0.069 vs 0.79±0.048,P<0.001; 1.17±0.069 vs0.53±0.023,P<0.0005,respectively),IGF-1 peptide contents[(196.66±14.9) ng·mg~(-1) vs(128.2±11.25) ng·mg~(-1),P<0.0005;(196.66±14.9) ng·mg~(-1) vs(74.43±5.33) ng·mg~(-1),P<0.0001,respectively] were reduced in liver tissues of diabetic rats.The IGF-1 gene downregulation varied with glucose controllevel of the diabetic state,and deteriorated graduallyfurther with duration of diabetes.By month 6,hepatic tissueIGF-1mRNA was 0.71±0.024 vs 1.12±0.056,P<0.001;0.47±0.021 vs 1.12±0.056,P<0.0005,respectively.IGF-1peptide was (114.35±8.09) ng·mg~(-1) vs (202.05±15.73)ng·mg~(-1),P<0.0005; (64.58±3.89) ng·mg~(-1) vs(202.05±15.73)ng·mg~(-1),P<0.0001 respectively.Serum IGF-1 was alsolowered in diabetic group with poor control of blood glucose.On week 2,serum IGF-1 concentrations were (371.0±12.5)ng·mg~(-1) vs(511.2±24.7) ng·mg~(-1),P<0.0005,(223.2±9.39)ng·mg~(-1) vs(511.2±24.7)ng·mg~(-1),P<0.0001 respectively.Bymonth 6,(349.6±18.62) ng·mg~(-1) vs(520.7±26.32) ng·mg~(-1),P<0.0005,(188.5±17.35 vs 520.7±26.32) ng·mg~(-1),P<0.0001,respectively.Serum IGF-1 peptide change was significantlycorrelated with that in liver tissue (r=-0.99,P<0.001).Furthermore,No difference was found in the above parametersbetween diabetic rats with euglycemia and non-diabeticcontrol group.CONCLUSION:The influence of diabetic status on IGF-1 gene expression in liver tissues is started from early diabeticstage,causing down regulation of IGF-1 expression,andprogresses with the severity and duration of diabetic state.Accordingly serum IGF-1 level decreases.This might indicatethat liver tissue IGF-1 gene expression is greatly affected indiabetes,thus contributing to reduction of serum IGF-1 level.
AIM: To explore the effect of diabetic duration and blood glucose levels on insulin like growth factor 1 (IGF-1) gene expression and serum IGF-1 level. METHODS: Diabetes was induced into Sprague Dawley rats by alloxan and then the rats were subdivided into different groups with The levels of IGF-1 peptide and serum IGF-1 concentration by enzyme-linked immunosorbent assay (ELISA) were measured by RT-PCR, .RESULTS: During early diabetic stage (week 2), incomparison with normal control group (NC), IGF-1 mRNA (1.17 ± 0.069 vs 0.79 ± 0.048, P <0.001; 1.17 ± 0.069 vs0.53 ± 0.023, P <0.0005 , respectively), IGF-1 peptide contents [(196.66 ± 14.9) ng · mg -1 (128.2 ± 11.25) ng · mg -1, P <0.0005, (196.66 ± 14.9) ng · mg ~ (-1) vs (74.43 ± 5.33) ng · mg ~ (-1), P <0.0001, respectively] were reduced in liver tissues of diabetic rats.The IGF-1 gene downregulation varied with glucose control level of the diabetic st ate, and deteriorated gradually with subsequent duration of diabetes.By month 6, hepatic tissue IGF-1 mRNA was 0.71 ± 0.024 vs 1.12 ± 0.056, P <0.001; 0.47 ± 0.021 vs 1.12 ± 0.056, P <0.0005, respectively. IGF- (114.35 ± 8.09) ng · mg -1 vs 202.05 ± 15.73 ng · mg -1, P <0.0005; (64.58 ± 3.89) ng · mg -1 vs 202.05 ± 15.73, ng · mg ~ (-1), P <0.0001 respectively.Serum IGF-1 was alsolowered in diabetic group with poor control of blood glucose.On week 2, serum IGF-1 concentrations were (371.0 ± 12.5) ng · mg ~ (511.2 ± 24.7) ng · mg ~ (-1), P <0.0005, (223.2 ± 9.39) ng · mg ~ (-1) vs (511.2 ± 24.7) ng · mg ~ P <0.0001 respectively.Bymonth 6, (349.6 ± 18.62) ng · mg -1 (520.7 ± 26.32) ng · mg -1, P <0.0005, (188.5 ± 17.35 vs 520.7 ± 26.32) ng · Mg -1, P <0.0001, respectively. Serum IGF-1 peptide change was significantlycorrelated with that in liver tissue (r = -0.99, P <0.001) .Furthermore, No difference was found in the above parametersbetween diabetic rats with euglycemia and non-diabeticcontrol group. CONCLUSION: The influence of diabetic status on IGF-1 gene expression in liver tissues is started from early diabeticstage, causing down regulation of IGF-1 expression, andprogresses with the severity and duration of diabetic state. Accordingly serum IGF-1 level decreases. This might indicate that liver tissue IGF- indiabetes, thus contributing to reduction of serum IGF-1 level.