Figure 3.
Major pathways of steroid hormone formation. Cholesterol carbon atoms are designated by conventional numbers and rings by conventional letters. The flow of steroidogenesis is generally downward and to the right. The top row is the pathway to progesterone and mineralocorticoids; the second row, the pathway to glucocorticoids; the third row, the 17-ketosteroids; the fourth row, 17ß-hydroxysteroids; and the bottom row, the 5α-reductase pathway to amplification and disposition of androgen. The dotted 17,20-lyase pathways are probably minor. The steroidogenic enzymes are italicized. Steroids before 3ßHSD action have the Δ 5-3ß-hydroxysteroid configuration, those formed by 3ßHSD are Δ 4-3-ketosteroids. Inset: 11ß-hydroxysteroid dehydrogenase interconversions of 11-oxysteroids, which occur in peripheral tissues. Abbreviations for enzymes are indicated in the side panel in approximate order of appearance.
Modified from Rosenfield et al (10).