Date Approved


Graduate Degree Type


Degree Name

Health Sciences (M.H.S.)

Degree Program

Biomedical Sciences

First Advisor

Chris Pearl

Second Advisor

Frank Sylvester

Third Advisor

Doug Graham

Academic Year



Estrogens, in addition to testosterone, are much more physiologically relevant to normal sperm production in the testis and overall male fertility than previously thought. Current use herbicides, such as atrazine, are known endocrine disruptors and have been suggested to disrupt male reproductive health. The purpose of this study was to investigate the effect of chronic atrazine exposure on male reproductive function in Sprague Dawley rats. Three groups of rats were treated until 7 months of age. The first group was the control vehicle and given only water. The second group was given a low dose of atrazine (0.1 mg/kg) and the third group was given a high dose of atrazine (10 mg/kg) via oral gavage to mimic the most common exposure to atrazine in humans. At 7 months of age, animals were euthanized and reproductive tissues were collected for analysis. Concentrations of testosterone were not significantly different between groups, but levels of serum FSH and estradiol were significantly increased in the high dose group relative to the control. Sperm/gram of the testis was significantly lower in the low dose group and daily sperm production was significantly lower in the high dose group. Collectively, these results support the hypothesis that sperm production and overall male reproductive health is significantly disrupted by chronic exposure to atrazine, and the relationship between estradiol and male fertility is sensitive to environmental contaminants.