Aldosterone is also secreted episodically, and the pattern closely resembles that for cortisol (Fig. 7.10). The mechanism and purpose of the episodic release of aldosterone, however, are unknown. The release of aldosterone is not caused by ACTH release since aldosterone secretion continues to follow an episodic pattern of release in the absence of ACTH, nor is it due to changes in plasma potassium or sodium levels. Furthermore, it is not entirely established whether the periodicity is caused by changes in angiotensin. Whatever mechanism is involved, it is apparently closely co-ordinated with that which causes ACTH release. As with cortisol, the pattern appears to be disrupted by disease.
