A previous study in an untreated girl with 17α-hydroxylase deficiency syndrome (17-OHDS)
indicated that in the absence of cortisol production, ACTH and corticosterone (B)
may interact to modulate the brain-pituitary-adrenocortical system. The ACTH-B interplay
was further examined in this patient under dexamethasone therapy and after withdrawal
of treatment. Plasma ACTH and B were highly correlated (r = 0.89) during two different
schedules of dexamethasone treatment and two weeks off treatment at all blood sampling
times (morning, afternoon or 24-h period). A logarithmic-sigmoidal relationship seems
to exist between ACTH and B secretion. The time course of ACTH-B relationship early
after withdrawal of therapy showed good parallelism between these two variables. Plasma
B may be a useful guide for monitoring therapy in 17-OHDS The present study also indicates
the ACTH-B interplay feedback set-points.
17α-Hydroxylase - ACTH - Corticosterone - Dexamethasone
