Irradiation therapy with131I-6β-Iodocholesterol of metapyralone induced adrenal hyperplasia in rats

Abstract

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.

Adrenal size and function after irradiation with131I-6β-iodocholesterol in rabbits

“…Similar to the results obtained with rats as experimental animals [10] the administration of 131I-6fl-iodocholesterol to rabbits had no influence on the body weight ( Table 1).…”

“…However, if it is used--analogous to the application of radioactive iodone in hyperactive or malignant thyroid disease--for the reduction of adrenal size and function its effect has been controversial. While the application of 1311-19-iodocholesterol in dogs was not followed by a size reduction of the adrenals [1], treatment of rats with I31I-6fl-iodocholesterol markedly reduced adrenal size [10]. Since the therapeutic effectiveness of 131I-6fl-iodocholesterol in malignant diseases of the adrenal cortex would obtain clinical interest, the animal experiment was extended to rabbits, and adrenal function was additionally recorded by the examination of serum cortisol.…”