IODINE CONCENTRATIONS IN THE RAT-KIDNEY MEASURED BY X-RAY-MICROANALYSIS - COMPARISON OF CONCENTRATIONS AND VISCOSITIES IN THE PROXIMAL TUBULES AND RENAL PELVIS AFTER INTRAVENOUS INJECTIONS OF CONTRAST-MEDIA

Purpose: To measure the iodine concentrations in the proximal tubules and renal pelvis after i.v. injections of contrast media (CM) at 1600 mg I/kg b.w., using a micropuncture technique and X-ray microanalysis. Material and Methods: The correlation between the viscosity of each C M and its iodine concentration was evaluated and the viscosity of the fluid in the proximal tubule and renal pelvis was estimated in rats. R esults: After iotrolan injection, the iodine concentration in the prox imal tubular fluid had increased to values about three times higher th an those reached with diatrizoate, iohexol and ioxaglate. Similarly, i otrolan tended to produce a higher iodine concentration in the renal p elvis than did the other CM. The urine viscosity in the renal pelvis w as much higher after the iotrolan injection than after the other CM in jections. Conclusion: High urine viscosity after iotrolan injection ca n at least partly explain our previous findings of a prolonged increas e in tubular hydrostatic pressure and a prolonged decrease in the sing le nephron glomerular filtration rate after administration of this CM.