Thesis (Ph.D.)--Boston University / The liver has been well established as being one of the most important organs involved in the metabolism of adrenocortical steroids. Liver perfusion, incubations with liver slices, homogenates and purified liver preparations all effect extensive changes on the steroid nucleus. In order to develop a step-wise scheme for the in vitro metabolism of a typical adrenocortical steroid and to localize enzyme systems effecting single metabolic transformations, 11-deoxycortisol was incubated with various rat liver homogenate fractions and the conversion products isolated and identified. The liver fractions were obtained by differential centrifugation of liver homogenates. This procedure afforded a 6000 x g supernatant, a 6000 x g residue (corresponding to mitochondria in sedimentation properties), a 78,000 x g residue (corresponding to microsoaes in sedimentation properties) and a 78.000 x g particulate free supernatant. Each tissue preparation was incubated with 11-deoxycortisol at 37° c. for two hours with flasks open to the atmosphere. A tissue to steroid ratio of approximately 1000:1, based on the initial weight of the liver, was employed [TRUNCATED].