THE ROLE OF NITRIC-OXIDE IN RADIATION NEPHROPATHY

Sufficient radiation will cause kidney injury with hypertension, azote mia, and death from renal failure. There is early endothelial injury a fter radiation, which could lead to a deficit of constitutive nitric o xide (NO) synthesis, with capillary thrombosis and hypertension, both of which are seen in radiation nephropathy. In a rat radiation nephrop athy model, the serial evolution of urinary cyclic guanosine monophosp hate (cGMP), a marker of kidney NO, was studied and a deficit in urina ry cGMP was found. This radiation-induced cGMP deficit was prevented b y high-dose Captopril treatment Low-dose Captopril treatment protected against radiation nephropathy without preventing the decrease in urin ary cGMP. An inhibitor of NO synthesis, L-N-arginine-methylester, did not blunt the beneficial effect of Captopril treatment. We conclude th at there is a deficit in urinary cGMP in radiation nephropathy, but th at prevention of this deficit is not essential in the prevention of ra diation nephropathy by Captopril.