Why would Arimidex cause my Total Testosterone level to go DOWN?!!

[killergoalie]

I've been on TRT since February of this year, when my TT was 41 ng/dl from a range of 242 - 827 ng/dl.

I inject 40mg of Test-Cyp SubQ 3 x per week, and on Nov 24 my TT level was 570 ng/dl from the same range as above.

On Nov 21st, I began taking .5 mg of Arimidex 3 x per week, 24 hours after each Test-Cyp injection. My E2 level on Nov. 24 was 92.6 pg/ml from a range of < 42.5 pg/ml.

I just did some blood work today, and my Total Testosterone level is down to 412.1 ng/dl from the same range as above.

I don't have the results yet from today's E2 test.

But why would Arimidex LOWER my testosterone? And by so much?