RENAL-FUNCTION IN STROKE-PRONE RATS FED A HIGH-K+ DIET

Renal function was assessed in prestroke and poststroke Kyoto-Wistar s troke-prone spontaneously hypertensive rats (SHRsp) fed high-K+ (2.11% ) and low-K+ (0.75%) diets containing 4% NaCl and in stroke-resistant SHR (srSHR) fed a low-K+ diet. Elevations in dietary K+ retarded the o nset of stroke development in SHRsp, but did not alter the life-span o f SHRsp between the onset of stroke and death. At ages <12 weeks, rena l function, measured by serum urea and creatinine levels and urinary p rotein loss, was comparable in high and low K+ fed prestroke SHRsp, an d age-matched srSHR At ages >12 weeks, hemorrhagic stroke rapidly deve loped in SHRsp. When compared with srSHR, prestroke SHRsp exhibited hi gher serum creatinine and urea levels, a greater excretion of protein into the urine, and lower serum albumin levels. The severity of the ab ove indices of renal failure was amplified in similar-aged poststroke SHRsp. Poststroke SHRsp also had elevated levels of hemoglobin in the urine. Increases in dietary K+ did not significantly decrease the seve rity of uremia and proteinuria in age-matched prestroke or poststroke SHRsp. It was concluded that a decrease in glomerular filtration, urem ia, and proteinuria preceded stroke development in SHRsp. The onset af proteinuria and uremia in SHRsp could potentiate stroke development. The latter indices of renal function were not altered by modifications in dietary Kf that retard stroke development in SHRsp.