Effect of I-131 incorporation on male rat reproductive system and the dose-dependent effect

Radioactive 131Iwas injected in single doses 9.25, 37, and 92.5 kBq to prepubertal (30-day-old) male rats. Iodine incorporation in doses 37 and 92.5 kBq resulted in some functional changes in the reproductive system of mature rats: blood testosterone level increased, its hypothalamic aromatization intensified, and biologically active LH level in the blood dropped. Incorporation of 9.25 kBq of 131-I had no effect on male reproductive system. A possibility of direct injury to rat testicles by 131I incorporation is suggested.