engleski

Leptin and Leptin Receptor Gene Variation and Human Obesity

Leptin is a protein hormone with important role in regulation of body weight, metabolism, reproductive function, modulation of immune response and angiogenesis. As a regulator of body weight, it operates by inhibiting food intake and stimulating energy expenditure and its concentration in the blood serum is proportional to the amount of body fat. Polymorphic leptin and leptin receptor genes have often been investigated as possible factors associated with human obesity. We tested polymorphisms G-2548A in the promoter region and A19G in exon 1 of the leptin gene and polymorphisms G-1041A in the promoter region, Arg109Lys in exon 4 and Arg223Gln in exon 6 of the leptin receptor gene for association with leptin concentration and obesity. Allelic frequencies of these polymorphisms show inter-poplational variation. A population-based association study was conducted in the population isolate of the Eastern Adriatic island of Vis, Croatia (N=243, age 22-85 yrs). Obesity was defined as BMI 30 kg/m2. Leptin concentration was significantly higher in the obese (65.3 ng/ml), than in the non-obese (19.9 ng/ml) and in women (44.6 ng/ml) compared to men (13.8 ng/ml). The results indicated significant association of -2548G variant and leptin concentration in men (p=0.013). No association of the other studied polymorphisms with leptin concentration was found, and none of the studied polymorphisms showed association with obesity (with leptin concentration, sex and age as covariates). The lack of association could be due to the complex pathogenesis of obesity, which involves a number of genetic and environmental factors.

leptin; polymorphism; obesity; anthropology; Croatia

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