Endogenous hydrocortisone, a possible factor contributing to the genesis of cushingoid habitus in patients on prednisone.

To establish if the cushingoid habitus in patients taking prednisone is associated with relatively high total or free prednisolone and low endogenous hydrocortisone concentrations in plasma, 15 stable renal transplant patients and 12 patients treated with prednisone for oral mucocutaneous vesiculo-erosive diseases were investigated. After the patients' usual prednisone doses, the areas under the plasma concentration time curve of total and free prednisolone were not different when the 14 patients without cushingoid appearance were compared to the 13 patients with cushingoid appearance. Patients with cushingoid habitus more frequently exhibited peak hydrocortisone levels within the normal range (6 of 14 vs. 1 of 13) and had higher areas under the plasma concentration time curve of hydrocortisone (median, range), i.e. 2672 ng/ml.min (0-21, 637 ng/ml.min) vs. 308 ng/ml.min (0-12, 495 ng/ml.min) compared to those without cushingoid appearance (P less than 0.05). These results indicate that pharmacokinetic differences of prednisone do not explain the presence or absence of cushingoid habitus and that there is an association between cushingoid habitus and endogenous hydrocortisone levels.