The influence of various genotypes on the metabolic activity of NAT2 in a Chinese population

Aim: To determine the phenotype and genotype of NAT2 in a Chinese population and study the influence of various NAT2 genotypes on the NAT2 activity. Methods: A reverse dot blot method was used to detect the genotype of NAT2 in 120 healthy Chinese subjects. All subjects were given a single dose of 500 mg sulphadimidine (SM2). The plasma concentration of SM2 and acetyl-SM2 (AcSM2) 6 h after administration was determined. Molar metabolic ratio (MR) was calculated by the ratio of AcSM2 to AcSM2+SM2. Results: Totals of 53 (44.2%), 47 (39.2%) and 20 (16.7%) subjects were homozygotes for wild type (wt/wt), heterozygotes for mutant (m/wt) and homozygotes for mutant (m/m), respectively. The MR of 120 subjects was 0.714 +/- 0.237. Twenty subjects (16.7%) were classified as poor metabolizers. All subjects in the m/m group were poor metabolizers. The MRs of the wt/wt, m/wt and m/m groups were 0.886 +/- 0.060, 0.719 +/- 0.089 and 0.246 +/- 0.105 (P < 0.001), respectively. There was a significant difference between different NAT2 m/wt genotypes (P < 0.001) and m/m genotypes (P < 0.001). MR correlated well with NAT2 genotypes (r=0.947). Conclusion: Various NAT2 genotypes have a significant impact on the metabolic activity of NAT2 in Chinese people.