In mice, like in humans, aldosterone biosynthesis is restricted to the zona glomerulosa. Unlike that in humans, the major glucocorticoid synthesized in mice is corticosterone (instead of cortisol), which is produced from the same precursor deoxycorticosterone by 11β-hydroxylase (CYP11B1) in the zona fasciculata (zF). Therefore, in mice, corticosterone is both an intermediate (zona glomerulosa [zG]) and end product (zF) of steroid biosynthesis.