QUANTITATION OF THE ACCELERATING EFFECT OF METYRAPONE ON CORTISOL METABOLISM

Publisher Website
Google Scholar
Abstract
Quantitation of the accelerating effect of metyrapone on cortisol metabolism was made by determination of the metabolic clearance rate (MCR) of exogenous cortisol during a metyrapone load. Six adrenalectomized patients were studied. The slope of cortisol concentrations in plasma was determined after i.v. administration of 0.3 mg cortisol/kg b.w. [body wt] with or without metyrapone (17.5 mg/kg b.w. h-1). In all 6 patients studied, the MCR of cortisol increased during metyrapone load from an average of 12.3 .+-. 5.0 (SD) 1/h to 29.6 .+-. 15.7 (SD) 1/h or corrected for body wt 3.0 .+-. 1.1 (SD) ml/kg b.w. min-1 to 7.1 .+-. 2.5 (SD) ml/kg b.w./min-1. The discrepancy discovered in clinical practice between the relatively small rise in plasma total corticosteroid concentration and the greater increase in urinary excretion of corticosteroid metabolites during the metyrapone test may be explained by these findings.