title: Paraoxonase polymorphism and its effect on male reproductive outcomes among Chinese pesticide factory workers.
abstract: BACKGROUND
  Serum paraoxonase has been associated with the metabolism of organophosphate pesticides in humans. Molecular analysis of the human paraoxonase gene (PON1) has revealed that Arg192 homozygotes have a greater detoxifying capability than Gln192 homozygotes. We examined the effects of PON1 genotypes on male reproductive outcomes and its interaction with exposure to organophosphate pesticides.
  
  
  METHODS
  We studied 60 Chinese pesticide-factory workers and 89 textile-factory workers who were unexposed to pesticides. The respective allele frequencies of Arg192 and Gln192 were 0.62 and 0.38. Pesticide exposure among 36 exposed subjects and 12 unexposed subjects, regardless of gender, was assessed by personal measurement of pesticide residues over an entire 8-hr shift and measurement of urinary p-nitrophenol level over a 24-hr period. We analyzed semen and hormone data collected from male subjects.
  
  
  RESULTS
  When the three PON1 genotypes were analyzed separately, a gene dose effect was not detected. We used the unexposed Arg192 homo/heterozygotes as the reference group, and re-analyzed the data. Exposed Arg192 homo/heterozygotes had significantly lower sperm count (chi 2 = 9.01, P < 0.01) and lower percentage of sperm with normal morphology (chi 2 = 4.18, P < 0.05) than the reference group. Both unexposed Gln192 homozygotes (chi 2 = 4.90, P < 0.05) and exposed Arg192 homo/heterozygotes (chi 2 = 10.00, P < 0.01) showed significantly lower sperm concentrations than the reference group. In addition, exposed Arg192 homo/heterozygotes had significantly higher serum LH levels (chi 2 = 7.94, P < 0.01) than the reference group.
  
  
  CONCLUSIONS
  Because of a small sample size, our findings are highly preliminary. Nevertheless, it calls for further investigation of the interaction between the PON1 genotype and organophosphate pesticide exposure on male reproductive outcomes.
authors.affiliation: Occupational Health Program, Harvard School of Public Health, Boston, MA 02115, USA.
authors.forename: C
authors.initials: C
authors.lastname: Padungtod
authors.forename: T
authors.initials: T
authors.lastname: Niu
authors.forename: Z
authors.initials: Z
authors.lastname: Wang
authors.forename: D A
authors.initials: DA
authors.lastname: Savitz
authors.forename: D C
authors.initials: DC
authors.lastname: Christiani
authors.forename: L M
authors.initials: LM
authors.lastname: Ryan
authors.forename: X
authors.initials: X
authors.lastname: Xu
mesh_terms: D000328:Adult; D000483:Alleles; D001120:Arginine / Q000235:genetics; D043303:Aryldialkylphosphatase; D002617:Chemical Industry; D002681:China; D004950:Esterases / Q000097:blood / Q000187:drug effects / Q000235:genetics*; D005260:Female; D005973:Glutamine / Q000235:genetics; D006579:Heterozygote; D006720:Homozygote; D006801:Humans; D008658:Inactivation, Metabolic; D007986:Luteinizing Hormone / Q000097:blood; D008297:Male; D008875:Middle Aged; D009596:Nitrophenols / Q000652:urine; D016273:Occupational Exposure; D010573:Pesticide Residues; D010575:Pesticides / Q000009:adverse effects / Q000378:metabolism; D011110:Polymorphism, Genetic / Q000235:genetics*; D012098:Reproduction / Q000187:drug effects / Q000235:genetics*; D013076:Sperm Count / Q000187:drug effects; D013081:Sperm Motility / Q000187:drug effects; D013094:Spermatozoa / Q000187:drug effects; D013783:Textile Industry; D013997:Time Factors
chemical_list: D009596:Nitrophenols; D010573:Pesticide Residues; D010575:Pesticides; D005973:Glutamine; D007986:Luteinizing Hormone; D001120:Arginine; D004950:Esterases; D043303:Aryldialkylphosphatase; C468406:PON1 protein, human; C024836:4-nitrophenol