Overnight metyrapone test by plasma corticoid radioassay

The measurement of total corticosteroid (cs) and 11-deoxycorticosteroid (deoxy cs) in serum by radioassay after overnight metyrapone test was discussed. 750 mg. (15 mg./kg. weight) of metyrapone was administered at 8 and 12 p.m. and at 4 a.m., and blood was taken at 9 a.m. on the second day to determine the total cs, and the deoxy cs by radioassay. The total cs level in normal human serum is 11.3 to 29.5 μg/dl and the deoxy cs level is 10.4 to 23.0 μg/dl. Determination of the total cs level in serum revealed that cases with less than 6 μg/dl total cs showed apparent reduction of ACTH secretion ability in the pituitary, cases of 6 to 10 μg/dl of total cs required more study of the clinical symptoms and examinations for diagnosis. Gases of less than 8 μg/dl total cs suggested that the pituitary and the adrenal cortical system might be inhibited. In patients with Cushing syndrome, cases of tumor revealed no increase of the total cs level while cases of bilateral proliferation showed remarkable increase of the level. Since metyrapone was administered during the sleeping time, side effects such as vertigo, nausea, depression of the blood pressure and so on were relieved. (Kanao, N.)