Glucose and lipid metabolism in relation to novel polymorphisms in the 5'-AMP-activated protein kinase gamma2 gene in Chinese.
The 5'-AMP-activated protein kinase (AMPK) behaves as a fuel sensor in glucose and lipid metabolism. We sequenced exon 1 and flanking regions of the gene encoding for the gamma2 subunit of AMPK (AMPKgamma2) and identified two novel common polymorphisms at position -26 and IVS1+43. We then studied these two polymorphisms in relation to plasma glucose, insulin resistance, beta-cell function, and serum lipids in 290 Han Chinese undergoing an oral glucose tolerance test and a frequently sampled intravenous glucose tolerance test. The -26C/T and IVS1+43C/T polymorphisms were in tight linkage disequilibrium (P=0.0002). In adjusted categorical analyses, the -26TT genotype tended to be associated with a higher risk of type 2 diabetes (odds ratio 4.52, P=0.07). The adjusted continuous analyses were confirmatory. -26TT subjects, compared with -26C allele carriers, had higher concentrations of plasma glucose, both fasting (7.3 vs. 6.1 mmol/L, P=0.02) and after oral glucose loading (area under the curve for glucose, 1984 vs. 1596 minmmol/L, P=0.002), and had lower acute insulin response to glucose (143 vs. 404, P=0.0005) and disposition index (151 vs. 459, P=0.008). In further adjusted analyses, we observed that IVS1+43TT subjects, compared with IVS1+43C allele carriers, had significantly higher serum concentrations of triglycerides (4.20 vs. 2.00 mmol/L, P<0.0001) and total cholesterol (5.88 vs. 4.99 mmol/L, P=0.01). In conclusion, in Chinese, the AMPKgamma2 polymorphisms might be associated with glucose and lipid metabolism.