Influence of ureteral catheter size on urinary flow rate and glomerular filtration rate in the rat.

The influence of ureteral catheter diameter on renal function was studied in rats during different diuretic states. Urinary flow rate and glomerular filtration rate were measured on each rat using ureteral catheters of two different internal diameters. In non-diuretic rats, urinary flow rate and glomerular filtration rate did not change according to the catheter diameter. In diuretic rats, urinary flow rate was from 40 to 70% lower with the smaller catheter. Differences became more marked as urinary flow rate increased. Glomerular filtration rates were about 20% lower when measured with small catheters. These results clearly demonstrate that the use of small diameter ureteral catheters during diuretic states leads to a decrease in glomerular filtration rate and urinary flow rate. The results also emphasize the importance of using large diameter catheters during such experimental conditions.