Disturbing Effects of Chronic Low-dose 4-Nonylphenol exposing on Gonadal Weight and Reproductive Outcome over One-generation

4-Nonylphenol (NP) is a surfactant that is a well-known and widespread estrogenic endocrine disrupting chemical (EDC). Although it has been known that the affinity of NP to ERs is low, it has been suggested that low-dose NP has toxicity. In the present study, the endocrine disrupting effects on reproduction, and the weight of gonads, epididymis, and uterus were evaluated with the chronic lower-dose NP exposing. This study was designed by following the OECD test guideline 443 and subjected to a complete necropsy. In male, NP had an effect on the weight of the testis and epididymis in both F(0) and F(1). In females, NP decreased the weight of ovary and uterus in F(0) but not in pre-pubertal F(1) pubs. Fertility of male and female in F(0) or F(1) was no related with NP administration. The number of caudal-epididymal sperm by body weight (BW) was not different between groups in both F(0) and F(1). Besides, the difference of the sperm number between generations was not detected. The number of ovulated oocytes was similar between groups in F(0), but significantly decreased in NP 50 group of F(1). The litter size and sex ratios of offspring in F(1) and F(2) were not different. The accumulated mating rate and gestation period were not affected by the NP administration. Those results shows that chronic lower-dose NP administration has an effect of endocrine disruptor on the weight of gonads and epididymis of F(0) and F(1) but not in reproduction. Based on the results, it is suggested that chronic lower-dose NP exposing causes endocrine disruption in the weight of gonad and epididymis but not in the reproductive ability of next generations.