Effects of pirimiphos-methyl (an organophosphate insecticide) on the fertility of adult male rats

Afr Health Sci. 2007 Mar;7(1):3-9. doi: 10.5555/afhs.2007.7.1.3.


Background: Organophosphate insecticides represent one of the most widely used classes of pesticides with high potential for human exposure in both rural and residential environments.

Objective: In the present study, we investigated the effects of pirimiphos-methyl (0, 2-diethylamino-6-methylpirimidin-4-yl O, O-dimethyl phosphorothioate), an organophosphothioate pesticide, on male rat reproductive performances.

Methods: A total of 24 adult Wistar rats were divided into 4 groups of 6 animals each and orally treated with 0, 41.67, 62.5 or 125 mg/kg of pirimiphos-methyl for 90 days.

Results: Results from the study showed a significant increase (p<0.05) in feed consumption, body weight gain, relative testis and epidiydimis weights and intra-testicular cholesterol level in rats receiving the test substance at doses of 62.5 or 125 mg/kg whereas a significant decrease (p<0.05) in serum total protein, sperm density and motility, fertility and parturition indices and pups sex-ratio (M/F) was recorded in animals treated with 125 mg/Kg of pirimiphos methyl. Histological findings also indicated enlargement of interstitial space, inhibition of spermatogenesis, rarefaction of Leydig cells and oedema in testes compared to control animals.

Conclusion: It could then be concluded that pirimiphos-methyl (62.5 and 125 mg/kg) is detrimental to the reproductive potentials of male rats.

Publication types

  • Evaluation Study

MeSH terms

  • Animals
  • Environmental Exposure / adverse effects*
  • Infertility, Male / chemically induced*
  • Insecticides / adverse effects*
  • Insecticides / blood
  • Male
  • Oligospermia / chemically induced
  • Organothiophosphorus Compounds / adverse effects*
  • Organothiophosphorus Compounds / blood
  • Rats
  • Rats, Wistar
  • Sperm Motility
  • Testis / pathology


  • Insecticides
  • Organothiophosphorus Compounds
  • pirimiphos methyl