Evaluation of renal functional reserve of contralateral kidney of two-kidney, one clip Goldblatt hypertensive rats.

To evaluate the presence of hyperfiltration in two-kidney, one clip (2K, 1C) Goldblatt hypertensive rats, micropuncture studies of the unclipped kidney were used to examine renal functional reserve (RFR) with glycine (G) infusion in normal (N) rats and 2K, 1C rats. Systemic hypertension in 2K, 1C rats was associated with significantly increased values of single-nephron glomerular filtration rate (SNGFR), glomerular plasma flow (QA) and glomerular capillary hydrostatic pressure (PGC) when compared with N rats. Glycine infusion produced a marked increase in SNGFR, QA and whole-kidney GFR in N rats. In contrast, no changes were observed in these parameters in 2K, 1C rats. Lack of response in 2K, 1C rats was related to the failure of renal vessels to dilate during G infusion. These results suggest that loss of renal functional reserve in systemic hypertension is dependent on an abnormal function of renal vascular resistances.