Objective Butyrylcholinesterase (BChE) activity has been associated with obesity, lipid concentrations, and CHE2 locus phenotypes. This, the aim of this study was to evaluate the effects of an energetic restriction diet intervention on anthropometrical and biochemical variables and on absolute and relative BChE activity in CHE2 C5+ and CHE2 C5- individuals. Subjects and methods One hundred eleven premenopausal obese women from Southern Brazil participated in an energetic restriction diet intervention (deficit of 2500 kJ/day) for 8 weeks. Their anthropometric and biochemical parameters were evaluated before and after the intervention. Plasma BChE activity was measured, and BChE bands in plasma and CHE2 locus phenotypes were detected by electrophoresis. Results The dietetic intervention decreased anthropometric and biochemical parameters as well as absolute BChE activity and relative activity of the G4 band. The CHE2 C5+ phenotype presented a different effect when compared with the CHE2 C5- phenotype. The CHE2 C5+ phenotype showed an effect in absolute BChE activity and in the relative activity of the G4 form, maintaining higher BChE activity regardless of the metabolic changes. Conclusion In our study, 8 weeks was not sufficient time to lower the body mass index to normal, but it was enough to significantly reduce the absolute BChE activity, which became similar to the levels in nonobese individuals. CHE2 C5+ individuals were resistant to the decrease in BChE activity compared to CHE2 C5- individuals. This shows that the diet did not affect the CHE2 and G4 fraction complex and that the products of the CHE2 locus in association with BChE have a role in energy metabolism, maintaining high levels of enzymatic activity even after dietary intervention.

Abstract Butyrylcholinesterase (BChE) activity and polymorphisms in its encoding gene had previously been associated with metabolic traits of obesity. This study investigated the association of three single nucleotide polymorphisms (SNPs) in the BCHE gene: -116G > A (rs1126680), 1615GA (rs1803274), 1914A < G (rs3495), with obesity and lipid metabolism markers, body mass index (BMI), total cholesterol (TC), low density lipoprotein cholesterol (LDL-C), high density lipoprotein cholesterol (HDL-C), triglyceride (TG) levels, and BChE enzymatic activity in obese (BMI≥30/n = 226) and non-obese women (BMI < 25/n = 81). BCHE SNPs genotyping was obtained by TaqMan allelic discrimination assay and by RFLP-PCR. Plasmatic BChE activity was measured using propionylthiocholine as substrate. Similar allele frequencies were found in obese and non-obese women for the three studied SNPs (p > 0.05). The dominant and recessive models were tested, and different effects were found. The -116A allele showed a dominant effect in BChE activity reduction in both non-obese and obese women (p = 0.045 and p < 0.001, respectively). The 1914A > G and 1615GA SNPs influenced the TG levels only in obese women. The 1914G and the 1615A alleles were associated with decreased plasma levels of TG. Thus, our results suggest that the obesity condition, characterized by loss of energy homeostasis, is modulated by BCHE polymorphisms.