Irradiation therapy with 131I-6beta-iodocholesterol of metapyralone induced adrenal hyperplasia in rats.

Marked weight reduction of rat adrenals was observed after 131I-6beta-Iodocholesterol administration whether or not the animals were treated with metapyralone. Damage or even histologic changes of the adrenals have not been found. Though the radiation dose is high with the applied dose of 131-i-6-beta-Iodocholesterol and might limit or even prevent its application in the treatment of human adrenal disease, the influence of endogenous irradiation on rat adrenals is obvious and justifies further investigations.