Plasma 6beta-hydroxycortisol measurements for assessing altered hepatic drug metabolizing enzyme activity

To study the usefulness of 6beta-hydroxycortisol (6betaOHF) measurements for assessing hepatic drug metabolizing enzyme activity, plasma 6betaOHF and cortisol were measured in 22 patients with alcoholic liver disease after at least 2 weeks of alcohol abstinence, in 5 patients with severe Cushing's syndrome and in 12 healthy non-drinker subjects. Blood samples were drawn under resting conditions during midnight, in the morning at 0800 h, after a 1-mg overnight dexamethasone test and after ACTH administration. Plasma cortisol and 6betaOHF were determined with radioimmunoassay. In patients with alcoholic liver disease, the plasma cortisol levels at midnight and 0800 h, as well as after the administration of dexamethasone and ACTH were not different from corresponding values measured in non-drinker controls. In addition, these patients with alcoholic liver disease had similar plasma 6betaOHF levels at midnight, 0800 h and after dexamethasone administration as compared to corresponding values in controls. By contrast, ACTH administration in patients with alcoholic liver disease resulted in a significantly (p<0.05) larger increase of plasma 6betaOHF (from 106 +/- 22 to 1102 +/- 106 ng/dl, mean +/- SE) as compared to that found in controls (from 74 +/- 3 to 337 +/- 76 ng/dl). The markedly increased 6betaOHF response to ACTH administration in patients with alcoholic liver disease was similar to that measured in patients with severe Cushing's syndrome, in whom increased and non-suppressible plasma cortisol levels were accompanied by markedly elevated plasma 6betaOHF levels. These results indicate that alcohol abstinence in patients with alcoholic liver disease is associated with an exaggerated 6betaOHF response to ACTH and that this abnormality may prove to be a clinically useful parameter for a sensitive detection of altered drug metabolism present in these patients.