Isoln from adrenal cortex: Wintersteiner, Pfiffner, J. Biol. Chem. 116, 291 (1936). Structure: Reichstein, Gtzi, Helv. Chim. Acta 21, 1497 (1938). Prepn from allopregnan-3β-ol-20-one 3-acetate: Rosenkranz et al., J. Am. Chem. Soc. 72, 4081 (1950); from pregn-5-ene-3β-ol-20-one: Ramirez, Stafie, ibid. 77, 134 (1955).