Potential tumor or organ imaging agents--31. Radioiodinated sterol benzoates and carbamates.

A series of radioiodinated benzoate and carbamate esters of cholesterol and pregnenolone wherein the acyl moiety served as the carrier for radioiodine was synthesized and evaluated as potential imaging agents for the adrenal cortex. 2,6-Dimethyl-3-iodobenzoyl and N-(4-iodophenyl) carbamoyl groups were chosen as the acyl functionality in an attempt to provide esters resistant to in vivo hydrolysis. Tissue disposition studies in rats revealed that their biodistribution was determined by the attached sterol carrier-the cholesterol esters demonstrated significant uptake at 24 h in the adrenal whereas the corresponding pregnenolone derivatives showed only slight affinity for steroid-secreting tissues at this time.