Exercise training does not alter cytochrome P-450 content and microsomal metabolism.

MICHAUD, T. J., K. A. BACHMANN, F. F. ANDRES, M. G. FLYNN, G. P. SHERMAN, and J. RODRIGUEZ-ZAYAS. Exercise training does not alter cytochrome P-450 content and microsomal metabolism. Med. Sci. Sports Exerc., Vol. 26, No. 8, pp. 978–982, 1994. The purpose of this investigation was to determine whether increased endurance exercise capacity alters total hepatic cytochrome P-450 content and cytochrome P-450 (CYP1A and CYP2B) mediated hepatic microsomal mixed-function oxidase drug metabolism. Twenty adult male Sprague-Dawley rats were randomly assigned to either a control (C) or an endurance trained group (ET). ET rats were progressively trained 5 d · wk-1 for 11 wk. Both C and ET rats were administered in random order single posttraining doses of probe drugs theo-phylline (probe for CYP1A) and anlipyrine (probe for CYP2B). Soleus muscle citrate synthase activity of ET rats was significantly greater (P 0.01). Therefore, it was concluded that strenuous endurance training of 11 wk duration did not alter total hepatic cytochrome P-450 content or CYP1A or CYP2B activity.