We studied DNA specimens from 102 women between 13 and 55 years of age (average age 35 years), who suf­fered from endometriosis, and 153 healthy women between 18 and 55 years old (average age 36.5 years). DNA was isolated from the peripheral venous blood by the standard method of phenol and chloroform extraction. Molecular and genetic analyses of the NAT2 gene poly­morphism were carried out with polymerase chain reaction (PCR) [17]. The reaction mixture, contained in 30 μL comprised 1 μg of genomic DNA, 600 μmoles each of dNTP, 67 mM of buffer Tris-HCl (pH 8.8), 6.7 μM of MgCl₂, 10 mM of β-mercaptoethanol, 16.6 mM of (NH₄)₂SO₄, 6.7 mM of EDTA, 170 μg/mL of bull serum albumin, 0.3 μL of Taq-polymerase (Sibenzym Company, Novosibirsk, Russia) and 10 pM of oligonucleotide pri­mers. The sequences of the primers were as follows: F 5'-GCT GGG TCT GGA AGC TCC TC-3'; R 5'-TTG GGT GAT ACA TAG ACA AGG G-3'.

      In order to reveal mononucleotide substitutions at positions 481, 590 and 857, the amplification products were subjected to enzymic hydrolysis over 2-10 hours with the restriction enzymes KpnI (that cleaves the transition C→T at position 481); TaqI (that cleaves the transition G→A at position 590) and BamHI (that cleaves the transi­tion G→A at position 857). The PCR products were ana­lyzed on electrophoresis in 8% polyacrylamide gel. Mspl fragments of plasmid pUC19 were used as markers of the DNA molecular mass (Table 1).

            We used the nomenclature proposed by Vatsis et al. [19] for the NAT2 alleles and examined the following: NAT2*4 (no substitutions), NAT2*5 (481T), NAT2*6 (590A), NAT2*7 (857A) (Table 1). Identification of the phenotypes took into account the genotypic variants according to all three examined loci: rapid acetylators (phenotype R-rapid) had no more than one mutant allele (genotypes NAT2*4/*4, NAT2*4/*5 and NAT2*4/*7), whereas slow acetylators (phenotype S-slow) had two and more mutant alleles (genotype NAT2*5/5, NAT2*5/5/6, NAT2*5/5/7, NAT2*5/6, NAT2*5/6/6, NAT2*5/6/7, NAT2*5/7, NAT2*5/7/7, NAT2*6/6, NAT2*6/6/7, NAT2*6/7, NAT2*6/7/7, NAT2*7/7) [9]. The statistical analyses of the results used the programs RxC (Rows x Columns) [20], BIOSYS-2 [21] and the Microsoft Excel ’97 software. The genotype frequencies were checked against distribution predicted by the Hardy-Weinberg rule.