Effects of a glyphosate-based herbicide on the oestrous cycle of rats

Objective:To determine the effects of a glyphosate-based herbicide on the oestrous cycle of rats.Methods:Fifteen adult Wistar rats were randomly divided into three groups.Group A served as the control group,while groups B and C received 250 and 500 mg/kg of glyphosate-based herbicide orally for five oestrous cycles,respectively.Stages of oestrous cycle,oestrous cycle index,length of cycle,oestrous cycle ratio,serum estradiol and progesterone levels were determined.Results:The proestrus and oestrus stages of the glyphosate-based herbicide groups increased significantly(P<0.05),although proestrus in group C was not significantly different from the control group.There was a significant decrease in the metestrus and diestrus of the glyphosate-based herbicide groups(P<0.05).The oestrous cycle index of the glyphosate-based herbicide treated groups was altered;this was characterized by an increase in the oestrous index and a decrease in the metestrus and diestrus indexes.The proestrus index of group B increased,while that of group C decreased.The length of the cycle of the glyphosate-based herbicide groups significantly decreased from the 1st and 3rd week till the end of the study in groups B and C,respectively(P<0.05).There was a significant increase in the oestrous cycle ratio of the glyphosate-based herbicide groups compared to the control group(P<0.05).Though the estradiol and progesterone levels of the glyphosate-based herbicide groups increased and decreased,respectively,they were not significantly different from the control group.Conclusions:Glyphosate-based herbicide at the doses of 250 and 500 mg/kg can alter the pattern of the oestrous cycle in rats.