Distribution and Retention of Plutonium-239 and Neptunium-237 in the Rat Adrenal

Abstract

The deposition of several radionuclides in the adrenal gland and the apparent lack of sensitivity of this organ to prolonged radiation from internal emitters has been reported by Rhoades (1). The microscopic distribution of plutonium deposited in the adrenal is referred to briefly in her article. More recently, a number of investigators have employed advanced histochemical and biochemical techniques to demonstrate adrenal malfunction after both external and internal radiation exposure. As a rule, the radiation has not been confined to the adrenal per se, and the adrenal deposition has not represented a major fraction of the total body burden of radionuclide. In view of the varied functional role of the adrenal and the sensitivity of biological systems to adrenal secretions, it is conceivable that even low levels of internal adrenal radiation could be of biological significance. It was of interest, therefore, to observe that detectable amounts of Pu239 and Np237 were retained in rat adrenals after administration of fairly massive doses of these radionuclides. A brief description of the retention and zonal distribution of these radioelements in the adrenal gland is presented in this paper.