Vascular lesions in hypertensive rats under salt loading: kidney renin and lysosomal enzymes.

1. Renal and cerebral vascular lesions occurred more often and earlier in spontaneously hypertensive rats (SHR) given a high salt diet than in SHR given a normal diet. 2. Kidney renin activity was low during high salt loading; the kidney renin activity of rats with hypertensive renal vascular lesions was moderately elevated. Kidney renin activity or cathepsin D activities were higher in stroke-prone SHR (SHRSP) aged 9 months than in stroke-resistant SHR (SHRSR). 3. beta-Glucuronidase, cathepsin D and deoxyribonuclease activities were greater in the kidney of Wistar/Kyoto (WK) rats or SHR when there were hypertensive vascular lesions. These three enzyme activities were also greater in the aorta of SHR aged 13-14 months than in the aorta of WK rats. 4. It was supposed that kidney renin activity and lysosomal enzyme activities were related to hypertensive vascular lesions.