Adrenocorticotropic Hormone (ACTH):

Adrenocorticotropic Hormone (ACTH) is a vital hormone produced by the anterior pituitary gland in the brain. It plays a central role in managing how the body responds to stress and regulates the production of cortisol, a key hormone released from the adrenal glands. Cortisol influences many critical functions, including metabolism, immune response, blood pressure regulation, and the body’s reaction to physical or emotional stress.

At MedEx Neo Clinic, we assess ACTH levels to understand how well your hypothalamic-pituitary-adrenal (HPA) axis is functioning. This axis is the body’s internal stress-response and hormone-regulation system. When functioning properly, the hypothalamus signals the pituitary gland to produce ACTH, which in turn stimulates the adrenal glands to release cortisol. Once cortisol levels are adequate, they send a feedback signal to the brain to reduce ACTH production, maintaining a healthy balance.

When is ACTH testing recommended?

MedEx Neo Clinic may recommend ACTH testing when there are symptoms or concerns related to adrenal insufficiency, excess cortisol production, or pituitary gland disorders. Common symptoms prompting testing include:

• Persistent fatigue and muscle weakness
• Weight changes (gain or unexplained loss)
• Low blood pressure or salt cravings
• Skin darkening (hyperpigmentation)
• Anxiety, depression, or poor stress tolerance

What do high ACTH levels mean?

Elevated ACTH levels can indicate that the pituitary gland is trying to stimulate the adrenal glands to produce more cortisol. This often occurs in:

• Addison’s Disease (Primary Adrenal Insufficiency): The adrenal glands do not produce enough cortisol, leading the pituitary to release more ACTH.
• Cushing’s Disease: Caused by a pituitary tumour that overproduces ACTH, resulting in excess cortisol.
• Ectopic ACTH Syndrome: Non-pituitary tumours (like small cell lung cancer) produce ACTH independently.

What do low ACTH levels mean?

Low ACTH levels may indicate:

• Secondary Adrenal Insufficiency: When the pituitary gland fails to produce adequate ACTH due to damage, tumour, or suppression.
• Exogenous Corticosteroid Use: Long-term use of steroid medications suppresses ACTH production.
• Adrenal Tumours: Tumours that produce excess cortisol can suppress ACTH through negative feedback.

Clinical Use at MedEx Neo Clinic:

• Diagnosing Adrenal and Pituitary Disorders: ACTH testing helps differentiate between primary (adrenal) and secondary (pituitary/hypothalamic) causes of hormone imbalance.
• Monitoring Hormonal Therapy: For patients undergoing steroid therapy or hormone replacement, ACTH monitoring helps ensure safe and effective dosing.
• Evaluating Unexplained Fatigue or Hormonal Symptoms: Especially when cortisol-related disorders are suspected.

ACTH & Cortisol Together:

At MedEx Neo Clinic, ACTH levels are often evaluated alongside serum cortisol or through dynamic testing such as the ACTH Stimulation Test. This helps confirm if the adrenal glands are responding properly to ACTH.

Normal Reference Range:

• Morning ACTH: 10 to 60 pg/mL (2.2 to 13.2 pmol/L)
• Evening ACTH: Typically lower due to natural daily rhythm

(Note: Levels vary slightly by lab and patient condition.)

Conclusion:

Monitoring ACTH is essential for diagnosing and managing disorders related to cortisol imbalance. At MedEx Neo Clinic, our hormone health specialists interpret ACTH results in the context of your overall health, symptoms, and related hormone levels to guide appropriate medical care and treatment.