[Rapid beta 1-24-corticotropin test in the exploration of the corticotropic axis. 71 cases]

The reliability of the beta 1-24 corticotropin test, which is both cheap and safe, in the assessment of the hypothalamic-pituitary-adrenocortical function was re-evaluated by comparing its results with those of the metyrapone test in 71 subjects: 30 controls and 51 patients with suspected pituitary-adrenal dysfunction. Response to a 500 micrograms intramuscular injection of beta 1-24 corticotropin was evaluated by measuring the 60 min plasma cortisol levels; 4.5 g of metyrapone divided into 6 doses were then administered orally and response was evaluated by measuring plasma 11-desoxycortisol levels. A highly significant correlation (r = 0.79; p less than 0.001) was observed between plasma cortisol and plasma 11-desoxycortisol levels. The results were best interpreted by expressing the values obtained as plasma cortisol concentrations which, in normal subjects are at least 21 micrograms/100 ml. The rapid beta 1-24 corticotropin test was found to be very reliable (sensitivity 90%, specificity 100%) to detect adrenal insufficiency, irrespective of the organs affected on the hypothalamic-adrenocortical axis.