Long-term follow-up of renal function in rats with unilateral hydronephrosis

In order to obtain more information on the long-term changes in renal function of hydronephrotic kidneys, we have measured the glomerular filtration rate (GFR) in rats with a congenital or an experimental unilateral hydronephrotic kidney (HK). In Brown Norway rats, with congenital hydronephrosis, the presence of an HK affected neither the total GFR nor the contribution of that kidney to the total GFR, during a follow-up of 70 weeks. In Wistar rats with experimental unilateral hydronephrosis two groups could be distinguished on the basis of the contribution of the HK to the total GFR. In the first, the contribution of the HK to the total GFR was not different from that of controls. This contribution as well as the total GFR remained similar to that of controls during the follow-up. In the second group, the contribution of the HK to the total GFR was reduced to 25%. In these rats the total GFR was slightly less than that of controls. The contribution of the HK to the total GFR remained unchanged for the next 56 weeks. It is concluded that the long lasting presence of unilateral hydronephrosis in rats does not necessarily result in a progressive loss of renal function with time.