ABSTRACT
This chapter deals with the development of adrenal imaging agents based on the cholesterol nucleus, including discussions regarding their specificity, metabolism, and mechanisms of localization at the cellular level. Although not the only agents demonstrating selective adrenal cortical specificity, the iodocholesterol derivatives have enjoyed the greatest clinical application since their introduction. The evolution of these iodocholesterol derivatives has been reviewed, and attention will be focused upon their metabolism and known parameters of adrenal cortical uptake. The amount of cholesterol that ultimately reaches the tissues is an important factor for both the maintenance of cellular integrity and the performance of biosynthetic function, and in addition has considerable bearing upon the estimation of adrenal gland uptake of the iodocholesterol derivatives. The importance of lipoproteins has also been demonstrated with respect to the control of certain intracellular enzyme systems that are rate limiting in the control of de novo synthesis of intracellular cholesterol.
