THE INTRARENAL VASCULAR ALTERATIONS IN RADIATION NEPHRITIS AND THEIR RELATIONSHIP TO THE DEVELOPMENT OF HYPERTENSION

Unilateral radiation nephritis was induced in 20 rats. This regularly resulted in the development of hypertension, but only after removal of the non-irradiated kidney. The increase in blood pressure was unrelated to uraemia. The irradiated kidneys showed typical micro-angiographic alterations consisting in a reduction of the cortical vasculature, whereas the medullary vasculature was well visualized. These alterations were ascribed to glomerular lesions induced by the irradiation. Renal arteriolosclerosis was mild or absent. The juxtaglomerular cell granulation was increased in the non-irradiated kidney early after irradiation, and tended to return to normal levels by prolongation of the interval from irradiation to removal of the non-irradiated kidney. It is suggested that: (i) the non-irradiated kidney exerts a protective action on the blood pressure level in unilateral radiation nephritis, (ii) the development of hypertension after removal of the non-irradiated kidney is due to an altered vascular pattern in the irradiated kidney resulting in a relative cortical ischaemia, and (iii) the radiation causes an acute damage of the juxtaglomerular cells, which, in the present experiments, was reversible.