Table of Contents
ISRN Toxicology
Volume 2012 (2012), Article ID 130846, 7 pages
Research Article

Herbicide Metolachlor Causes Changes in Reproductive Endocrinology of Male Wistar Rats

1Department of Pharmacy, State University of Centro-Oeste, R. Simeao Camargo Varela de Sa, 03, 85040-080 Guarapuava, PR, Brazil
2Department of Animal Reproduction, Faculty of Veterinary Medicine, University of Sao Paulo, Avenida Prof. Dr. Orlando Marques de Paiva, 87, 05508-270 Sao Paulo, SP, Brazil

Received 9 February 2012; Accepted 28 February 2012

Academic Editors: S. M. Waliszewski and K. Yamasaki

Copyright © 2012 Francielle Tatiane Mathias et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


S-metolachlor is a chloroacetanilide herbicide widely used in the agriculture to control weeds and was demonstrated that it increases the activity of the aromatase enzyme in cell cultures, which may culminate as endocrine disruption action in vivo. To investigate this hypothesis, prepubertal Wistar male rats were exposed to metolachlor (5 or 50 mg/kg/day, NOEL for reproductive toxicity: 23.5–26.0 mg/kg/day) from PND23 (postnatal day) to PND53. During this period, the growth of the animals and the age and weight at puberty were recorded. In PND53, tissues were collected and the analysis of LH, FSH, testosterone, dihydrotestosterone (DHT), estradiol serum concentrations, morphometric evaluation of the seminiferous epithelium, and weight of the testes and the seminal vesicle (undrained and drained) was performed (Statistical difference: 𝑃 < 0 . 0 5 ). Metolachlor caused an increase in serum concentrations of testosterone, estradiol, and FSH and a reduction in DHT but did not alter the LH. There were also observed a higher amount of fluid in the seminal vesicles, precocious puberty, and changes in morphology of the seminiferous epithelium of treated animals. We demonstrated in this paper that prepubertal exposure to S-metolachlor caused changes in reproductive endocrinology of male rats.