Renal tissue and urinary kallikrein activity in two-kidney, one-clip hypertensive rats

Renal tissue and urinary kallikrein activity were studied to assess the role of the renal kallikrein-kinin system in two-kidney, one-clip hypertensive rats. Body weight, urine volume, systolic blood pressure and urinary kallikrein activity were measured in 11 hypertensive rats and 6 normotensive rats 1, 4, 8 and 12 weeks after clipping or sham operation. The hypertensive rats used in the present study had systolic blood pressures of over 180 mm Hg 12 weeks after the operation and presented polyuria with a reduction in weight gain, which placed them in the malignant hypertension category. Urinary kallikrein activity in hypertensive rats significantly decreased from 21.7 +/- 13.3 nkat/day at 1 week to 11.6 +/- 5.5 nkat/day at 12 weeks after clipping (p less than 0.05), while urinary kallikrein activity in normotensive rats significantly increased from 23.6 +/- 8.9 nkat/day at 1 week to 43.7 +/- 16.2 nkat/day at 4 weeks after the sham operation. Significant differences were observed in urinary kallikrein activity between hypertensive rats and normotensive rats 4 and 12 weeks after the operation (p less than 0.05). Renal tissue kallikrein activity from bilaterally nephrectomized kidneys was investigated 12 weeks after the operation. No significant difference in tissue kallikrein activity was found between the two kidneys of the hypertensive rats. However, tissue kallikrein activity was significantly lower in the contralateral kidney of hypertensive rats as compared to the same kidney of normotensive rats (2.13 +/- 0.73 nkat/g in hypertensive rats vs. 3.05 +/- 0.69 nkat/g in normotensive rats, p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)