The eosinopenic response to 40 mg of cortisol given intravenously was studied in 19 unselected asthmatics (group A) and in 6 asthmatics who exhibit clinical resistance to cortisol's antiasthma effect (group B). The changes in total eosinophil counts were -35%, -77%, and -73% in group A; and -10%, -36%, and 3.6% in group B at 2, 4, and 6 hr after administration.
Cortisol turnover studies in four subjects from each group were done using a tracer dose of tritium-labeled cortisol immediately followed by 40 mg of unlabeled cortisol intravenously. Plasma levels were measured at 30, 60, 90, and 120 min; 6-hr urine collections were made. Cortisol half-life values in group A were 123, 133, 120, and 132 min; in group B they were 81, 96, 75, and 90 min.
Thus, asthma requiring unusually large doses of steroid for control may be associated with a decreased eosinopenic response to cortisol and an accelerated plasma cortisol clearance.