3-Ethyl and 3-methyl ethers of 19-iodocholesterol as potential adrenal scanning agents.

19-Iodocholesterol-131I, though useful as an adrenal scanning agent, was found to be unstable. However, the substitution of methoxyl and ethoxyl groups for the hydroxyl group in the 3 position rendered these derivatives much more stable in solid form than the parent compound. They showed concentration in the adrenals of dogs similar to that of 19-iodocholesterol itself and therefore may be useful as adrenal scanning agents.