Mineralocorticoid Biosynthesis The three major factors that control the biosynthesis and release of aldosterone are angiotensin II, adrenocorticotrophic hormone (ACTH), and potassium. Of these, angiotensin II is almost certainly the most important; various factors can alter the adrenal responsiveness to this hormone. The major pathway involved in the biosynthesis of aldosterone is probably as shown in Fig. 7.5, although others almost certainly exist and may be important in particular conditions. See later: • Hydroxylation of Steroids