In moderate and major stress situations, cortisol concentrations in patients without hypothalamic-pituitary-adrenal disease were higher after stimulation with 250 microg compared with 1 mug ACTH. Data from our study give insight into the physiological adaptations of the hypothalamic-pituitary-adrenal axis to stress.

The more pronounced increase in FC seen during stress as compared with the ACTH test suggests that this test does not adequately anticipate the FC levels needed during severe stress.