Effect of cypermethrin on the ovarian activity and its impact on fertility and pubertal onset of offspring

Oral (by gavage) administration of cypermethrin (CYP), (3 doses; 1.38, 2.76 and 5.52Â mg/kg body weight) to female mice for two durations (6Â weeks and 12Â weeks), caused significant reduction in the number of estrous cycles per month, serum levels of estradiol, total number of healthy ovarian follicles and number of corpora lutea whereas there was an increase in number of atretic follicles of all categories compared to controls. Mice of all treated groups after 6Â weeks treatment showed 100% fertility. It was 80% in low and medium doses and 60% in high dose treatment after 12Â weeks. There was a significant delay in the onset of puberty and reduction in number of estrous cycles of progeny of medium and high dose CYP treated mice mated with normal males. Number of estrous cycles per month, healthy follicles, corpora lutea and serum levels of estradiol, were not reversible within 6Â weeks after cessation of medium and high dose treatment for 12Â weeks. The study first time reveals that reversibility of the reproductive toxic effects of CYP depends on quantum and duration of exposure. Keywords: Cypermethrin, Pyrethroid, Fertility, Estrous periodicity, Estradio