Date of Award

Spring 1976

Document Type



Life & Environmental Sciences

First Advisor

James Manion

Second Advisor

John Christenson

Third Advisor

John Ward


Fifteen female Holtzman rats were used to make correlations between ability to perform a previously learned discrimination task and stage of the estrous cycle. The rats were then injected subcutaneously, eight with 10/g of estradiol-17b, and seven with 3mg of progesterone. A comparison was made of their performances of the discrimination task. No correlation was found between ability to discriminate and stage of the estrous cycle. However, rats injected with estradiol-17b scored significantly better than did rats injected with progesterone. The results indicate that estrogen and progesterone significantly affect the rat’s ability to successfully perform a discrimination task. Possible explanations for this relationship are discussed.