The effects of estradiol on cardiac muscle electrophysiology in orchiectomized rat model: a new insight to side effects caused by castration

M. Ayaz, M. Akand, Y. Kucukbagriacik, D. Dursunoglu

Department of Biophysics, Selcuk University, School of Medicine, Konya, Turkey. ayaz72@yahoo.com

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• Cardiology

OBJCTIVE: Although the testosterone has a protective effect on heart, patients having maximal androgen blockade due to prostate cancer resembles endothelial dysfunction and cardiac problems when compared to normal population. We aimed to test the effect of 17 beta estradiol on the orchiectomized male rat heart electrophysiology and ion channel expression levels.

MATERIALS AND METHODS: This study was conducted on 27 male rats with 4 groups (healthy, orchiectomized, orchiectomized+17 beta estradiol treated and orchiectomized+vehicle treated). Action potentials and contractions were recorded simultaneously, while expressions of the calcium and potassium ion channels were measured.

RESULTS: Testosterone depletion for 4 weeks has caused a significant prolongation in the action potential durations and decrease in maximal contraction force as well as a deceleration. While this depletion suppressed expression of potassium channels, it increased the expression of calcium ion channels. Application of estradiol on the other hand, except for the calcium ion channel expression, had no positive effect on the tested parameters.

CONCLUSIONS: Testosterone has a markedly important and protective effect on male cardiac muscle preparations while estrogen does not have any. It is predicted that testosterone has showed this effect by means of modulation of some key points of excitation-contraction pairing of cardiac muscle.

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