Plant growth regulator (4-chlorophenoxy acetic acid) increases apoptosis in gonads of rats without changing hormonal levels.

Plant growth regulators are considered to leave minimal amounts of remnants and therefore cause no significant side effects in humans. In this study, we aimed to investigate the hormonal and histopathological effects of 4-chlorophenoxy acetic acid (4-CPA), a commonly used plant growth regulator, on the gonadal functions of rats. The study was implemented on 64 Wistar albino rats (20 days old). Forty-eight rats received 4-CPA every day until 50 days of age. The rats were randomized into 4 groups (a control group and three 4-CPA groups with doses of 25, 50 and 100 mg/kg/day); each group was further divided into males and females, making a total of 8 groups. The levels of FSH, LH, testosterone, estradiol, leptin, inhibin-B and neuropeptide-Y were measured. Histopathological examination of the testes and ductus deferens in male rats, and ovaries and uterus of female rats (caspase-3 and -9 immunoreactivity) was performed. Although hormone levels were similar between the groups, rats that received 4-CPA showed significantly higher degrees of apoptosis compared to the control group (p < 0.001) and increased doses of 4-CPA were directly correlated with the amount of apoptosis (p < 0.001). 4-CPA induced apoptosis in the gonads of rats without concurrent changes in plasma hormone levels.