Plasma 11-deoxycortisol, androstenedione, testosterone and ACTH in comparison with the urinary excretion of tetrahydro-11-deoxycortisol as indices of the pituitary-adrenal response to oral metyrapone
Plasma levels of ACTH, 11-deoxycortisol, androstenedione and testosterone and urinary tetrahydro-11-deoxycortisol were determined during a two day oral metyrapone test using doses of 1.5 g every 6 h. The level of 11-deoxycortisol 48 h after the start was distinctive regarding the assessment of pituitary ACTH secretory capacity. The rise of androstenedione concentration after 48 h is distinctive in a similar way, whereas ACTH determination is of little diagnostic value in this respect. Further, an increase in testosterone level can be observed in cases of low basal testosterone production. This increase is probably the result of peripheral conversion of androstenedione to testosterone. Where the basal testosterone concentration was high, no change could be measured.