ABSTRACT
Objective To investigate the characteristics of plasma glucose, insulin secretion and changes of insulin resistance (IR) after a glucose load in obese children, and to predict islet β-cell function. Methods A total of 635 obese children were classified into normal glucose tolerance (NGT) group (n=483), impaired glucose regulation (IGR) group (n=112) and type 2 diabetes mellitus (DM) group (n=40) based on their glucose levels. Subjects were also divided into G1 group (23 kg/m2≤BMI<30 kg/m2, n=393) and G2 group (BMI≥30 kg/m2, n=242) based on their different BMI levels. Level of fast plasma glucose (FPG, 0.5 h-PG, 1 h-PG, 2 h-PG and 3 h-PG) and insulin (FINS, 0.5 h-INS, 1 h-INS, 2 h-INS and 3 h-INS) were measured 0 h, 0.5 h, 1 h, 2 h and 3 h after a glucose load. Insulin resistance index (HOMA-IR), whole body insulin sensitivity index (WBISI), function of pancreatic beta-cell (HOMA-β), first-phase insulin secretion index (ΔI30/ΔG30) and area under curve of insulin (AUCI) were calculated and compared between groups. Results The value of insulin at each time point was significantly higher in IGR group than that of NGT group. The values of insulin at 0.5 h, 1 h, and 2 h were significantly lower in DM group than those of IGR group, respectively (all P<0.05). Compared with NGT group, AUCI, HOMA-IR and HOMA-β increased, but WBISI and ΔI30/ΔG30 decreased in IGR group (all P<0.05). HOMA-IR increased but WBISI, HOMA-βandΔI30/ΔG30 decreased in DM group (all P<0.05). Compared with IGR group, AUCI, HOMA-βandΔI30/ΔG30 decreased in DM group (all P<0.05). Values of FINS, AUCI, HOMA-IR, 2h-PG and HOMA-βwere significantly higher in G2 group than those of G1 group, but WBISI decreased (all P<0.05). There were no significant differences in FPG and ΔI30/ΔG30 between these two groups. Conclusion From NGT, IGR to DM, the peak of insulin secretion is postponed, insulin resistance is getting heavier and the compensation of insulin secretion after a glucose load is increased first and then decreased.
ABSTRACT
Objective To investigate the possible association of circulating components of GH-IGFs-IGFBPs system with the GHR-exon 3 genotype in idiopathic short stature (ISS) children. Methods Genomic DNA was extracted and isolat-ed from peripheral leukocytes in 108 ISS children. GHR-exon 3 polymorphism was analyzed with multiplex poly-merase chain reactions (PCR) assay. According to the results of genotype, ISS children were divided into GHRfl group and GHRd 3 group. The height and weight were recorded in two groups. The body mass index (BMI) and BMI standard deviation score (SDS) were measured. The serum levels of insulin-like growth factor (IGF)-1, IGF-binding protein (IGFBP)-3, IGF-1 SDS and IGFBP3 SDS were calculated. GH stimulation test was used to measure the serum GH peak value. Fifty-five ISS chil-dren were treated with recombine human GH [0.15 IU/(kg·d)] for three months to analyse the association of IGF-1 response of GH treatment and genotypes. Results There were 63 GHRfl and 45 GHRd3 in 108 ISS children. There were no signifi-cant differences in BMI, IGF-1, IGFBP3, GH peak, IGF-1 SDS and IGFBP3 SDS between two groups (P>0.05). Multiple stepwise regression analysis showed that age, IGFBP3, lg (BMI) and lg (GH peak) were influencing factors of lgIGF-1 (P<0.05). In 55 ISS children treated with rhGH, there were 34 cases of GHRd3. The differences of △IGF-1 and △IGF-1 SDS were higher in GHRd3 group than those of GHRfl group (n=21). Conclusion The GH sensitivity may be a risk factor in ISS children, which may not be related with GHR polymorphism.