Cortisol

Full Definition

Cortisol is the primary glucocorticoid hormone produced by the adrenal cortex in response to ACTH stimulation. It regulates glucose metabolism, immune function, and stress response. Cortisol exhibits strong circadian variation, with peak levels in the morning and lowest levels at night. Testing methods include serum, saliva, and 24-hour urine collections, each with specific clinical applications for diagnosing Cushing's syndrome or Addison's disease.

Usage

Usage note: Specify collection time and method; note circadian variation in documentation.

In Context

• "Morning cortisol levels below 5 μg/dL suggest adrenal insufficiency." — Endocrinology assessment
• "Late-night salivary cortisol is preferred for Cushing's syndrome screening." — Laboratory protocol