Correlation between microsatellite polymorphisms in ob gene 3′ flanking region with overweight and obesity in Chinese Han ethnicity in Shanghai / 第二军医大学学报

Objective: To investigate the correlation between the microsatellite polymorphisms in ob gene 3′ flanking region with obesity in Chinese Han ethnicity in Shanghai. Methods: The genotypes of polymorphisms in A gene 3′ flanking region were determined by PCR in 232 Chinese Han subjects (including 130 obese patients and 102 normal controls). The clinical data, including height, weight, waist circumference, hip circumference, body mass index, waist-to hip ratio (WHR), blood glucose, serum insulin, blood lipidsland uric acid, were compared between the 2 groups. Results: No significant difference of genotype frequency (I/I 0.115, I/ II 0.331, II/II 0.554 vs I/I 0.059, I/II 0.333, II/II 0.608) and allele frequency (I 0.281, II 0.719 vs I 0.225, II 0.775) of A gene 3′flanking region was observed between the 2 groups. In obese group, patients with I + II genotype was associated with increased WHR compared with those with II/II genotype (0.91±0.05 vs 0.86 ± 0.03, P=0.047). Logistic regression analysis showed that WHR was independently correlated with A gene polymorphisms (P=0.042). Conclusion: Polymorphisms in ob gene 3′ flanking region are correlated with central obesity in obese patients of Chinese Han ethnicity in Shanghai.

The Separate and Combined Effects of Insulin, Dexamethasone and Growth Hormone on the OB Gene Expression and Leptin Secretion from Cultured Human Visceral Adipose Tissue

PURPOSE: We investigated the hormonal control of OB gene expression and leptin secretion in cultured human visceral adipose tissue. METHODS: Visceral adipose tissues were cultured for up to 48 hrs in modified Eagle's medium with varying concentration of hormones : Control(no hormone), bovine insulin(100 nM), Dexamethasone(DEX, 100 nM), growth hormone(GH, 40 ng/mL), insulin + DEX(100 nM each), insulin + DEX + GH(100 nM insulin and DEX, 40 ng/mL GH). Quantitative analysis of leptin mRNA was performed by competitive reverse transcription polymerase chain reaction, and leptin secretion in culture medium was measured by IRMA using a commercial kit. RESULTS: The addition of dexamethasone to the medium significantly increased OB gene expression and leptin secretion(P<0.05). Unlike dexamethasone, insulin did not affect OB gene expression and leptin secretion. Both insulin and dexamethasone, at high concentration, significantly stimulated leptin secretion compared with basal values(P<0.05). Leptin gene expression was not significantly increased by GH treatment alone, however GH, in combination with high concentrations of insulin and dexamethasone, attenuated the stimulatory effects of high concentrations of insulin and dexamethasone. CONCLUSION: Insulin cannot increase leptin secretion without the presence of dexamethasone. The mechanism suggested is that insulin may increase leptin secretion in cytoplasm only after dexamethasone increases the expression of OB gene. Further studies are necessary to elucidate the mechanism of the action of insulin on leptin secretion after increasing OB gene expression by dexamethasone.

Correlation between microsatellite polymorphisms in ob gene 3′ flanking region with overweight and obesity in Chinese Han ethnicity in Shanghai / 第二军医大学学报

Objective:To investigate the correlation between the microsatellite polymorphisms in ob gene 3′flanking region with obesity in Chinese Han ethnicity in Shanghai.Methods: The genotypes of polymorphisms in ob gene 3′flanking region were determined by PCR in 232 Chinese Han subjects(including 130 obese patients and 102 normal controls).The clinical data,including height,weight,waist circumference,hip circumference,body mass index,waist-to hip ratio(WHR),blood glucose,serum insulin,blood lipids,and uric acid,were compared between the 2 groups.Results: No significant difference of genotype frequency(Ⅰ/Ⅰ 0.115,Ⅰ/Ⅱ 0.331,Ⅱ/Ⅱ 0.554 vs Ⅰ/Ⅰ 0.059,Ⅰ/Ⅱ 0.333,Ⅱ/Ⅱ 0.608) and allele frequency(Ⅰ 0.281,Ⅱ 0.719 vs Ⅰ 0.225,Ⅱ 0.775) of ob gene 3′flanking region was observed between the 2 groups.In obese group,patients with Ⅰ+Ⅱ genotype was associated with increased WHR compared with those with Ⅱ/Ⅱ genotype(0.91?0.05 vs 0.86?0.03,P=0.047).Logistic regression analysis showed that WHR was independently correlated with ob gene polymorphisms(P=0.042).Conclusion: Polymorphisms in ob gene 3′ flanking region are correlated with central obesity in obese patients of Chinese Han ethnicity in Shanghai.