Answer:
When ACTH level is too high, cortisol production is increased to restrain ACTH release from the pituitary gland
When ACTH level is too low, the hypothalamus produces corticotropin releasing hormone( CRH) to stimulate the pituitary gland to produce ACTH
Explanation: ACTH levels vary according to the time of the day, they are at the highest levels in the morning and rise in response to stress.