Effect of metyrapone on cortisol binding capacity in plasma.

Metyrapone was added in vivo to six different samples of normal plasma (0.1 mg/ml plasma) and administered orally (30 mg/kg) to 5 adrenalectomized patients. An increased ratio free, non protein-bound cortisol: total cortisol in plasma was demonstrated after metyrapone in all six in vitro studies and in 4 of the 5 adrenalectomized patients. These findings may explain the accelerating effect of metyrapone on cortisol metabolism.