Plasma ACTH levels are high between these following hours: (A) 4 PM and 8 PM, (B) 4 AM and 10 AM, (C) 10 AM and 3 PM, (D) 10 AM and 2 PM
Answer is B. (B) 4 AM and 10 AM # ACTH the primary stimulator of adrenal cortisol production is synthesized by pituitary in response to CRH, which is released by hypothalamus.> Plasma ACTH and cortisol levels exhibit peaks at 6-8 AM and nadirs at 11 PM.> Referene values: 10-60 pg for AM values. No established reference values for PM.