1. Urinary kallikrein, renal tissue kininogenase activity, and plasma kininogen were measured during the development of hypertension in rats, either with left renal artery clamped and contralateral kidney intact (Goldblatt 2-kidney) or removed (Goldblatt 1-kidney). Plasma urea, plasma volume and blood volume were also measured.
2. In Goldblatt 2-kidney rats, urinary kallikrein was not significantly different from that of sham-operated rats up to the 5th post-operative week even though at this time the Goldblatt 2-kidney animals were hypertensive. Urinary kallikrein started to decrease at week 8. Plasma kininogen was significantly elevated 5 and 10 weeks after surgery and returned to normal by week 15. No changes in renal tissue kininogenase activity were observed. Plasma urea and plasma and blood volumes were normal 5 weeks after, but significantly increased at 10 and 15 weeks after surgery.
3. In Goldblatt 1-kidney rats from the fifth week urinary kallikrein and renal kininogenase activity were significantly decreased compared with unilaterally nephrectomized rats, whereas plasma kininogen, plasma urea and plasma and blood volumes were significantly elevated.
4. These results show important differences in the kallikrein system between the Goldblatt 1-kidney and 2-kidney models of renovascular hypertension in rats.