[The radioprotective effect of iodine and its preventive action on renal calcification (author's transl)]

The protective effect of iodine against injurious damage caused by ionizing radiation was studied in 26 rats irradiated with cobalt-60 gamma rays as a single dose of 1000 rads (10 joule/kg). Twelve rats were pretreated 13 times every second day before irradiation. After irradiation they were treated daily during 21 days with 2.5 to 3.0 mg iodine given subcutaneously along with 9 mg Ca2+ (as gluconolactobionate) intramuscularly. In addition, they received 500 micrograms of iodine in their food daily. 67% of the iodine-treated rats remained alive after 30 days in contrast to 36% of the control rats which received Ca2+ only. 10 further rats which received neither iodine nor Ca2+ died within 3 to 5 days after irradiation. Deposition of calcium in the renal parenchyma was observed in 12 out of the 14 control rats, but only in 2 out of the 12 iodine-treated rats. It can be concluded from the results that iodine has a protective effect on ionizing radiation. It is assumed that iodine promotes the energy-conserving mechanism in mitochondria and also prevents the irradiation-induced decrease in calcium efflux.