[Immediate suppression of endogenous cortisol secretion after single oral administration of 6-alpha-methylprednisolone].

Plasma samples from 5 asthma patients were taken in 4-h intervals before and 1, 2, 4 and 6 h after the oral application of 100 mg methylprednisolone. Reversed-phase HPLC allowed simultaneous measurement of both endogenous hydrocortisone and exogeneous methylprednisolone. Suppression of endogeneous hydrocortisone secretion occurs immediately after administration of a single oral dose of an exogeneous glucocorticoid and cannot be avoided by morning application.