Autoradiographic changes in the kidney of the whole-body sublethally x-ray irradiated rat

203Hg-hydroxymersalyl uptake / gram of kidney (HU), renal autoradiographic and histologic aspect after 800 R X-ray whole-body rat irradiation was studied. Twenty-four to seventy-two hours after irradiation, HU increased, while tubular autoradiographic granularity decreased. Their return to the control levels occurred gradually within two weeks. The relations of these findings to the early circulatory and dystrophic changes, as well as to the subsequent postirradiation restoring renal process are discussed.