Effects of Chronic ACTH Excess on Human Adrenal Cortex

Area of Science:

• Endocrinology
• Molecular Biology

Background:

• Chronic ACTH excess causes Cushing's syndrome.
• This leads to excess cortisol, adrenal androgens, and mineralocorticoids.

Purpose of the Study:

• To investigate the effects of chronic ACTH excess on adrenal function and growth.

Main Methods:

• Analysis of hormone levels (cortisol, androgens, mineralocorticoids, aldosterone, testosterone).
• Assessment of adrenal gland size and composition (protein, RNA, DNA synthesis).
• Exploration of growth factor involvement in ACTH-induced adrenal growth.

Main Results:

• Chronic ACTH excess results in sustained cortisol and 11-DOC elevation, causing mineralocorticoid excess and suppressed aldosterone.
• Adrenal androgen levels are altered, affecting testosterone in males and females.
• Prolonged ACTH stimulation induces adrenocortical hyperplasia via increased protein, RNA, and DNA synthesis, potentially mediated by autocrine growth factors.

Conclusions:

• Chronic ACTH excess leads to Cushing's syndrome characterized by mineralocorticoid excess and suppressed aldosterone.
• Adrenocortical hyperplasia is a key adaptation to prolonged ACTH stimulation.
• Autocrine growth factors likely mediate the growth-promoting effects of ACTH on the adrenal cortex.