TY - JOUR T1 - Loss of Sodium Modulation of Plasma Kinins in Human Hypertension JF - Journal of Pharmacology and Experimental Therapeutics JO - J Pharmacol Exp Ther SP - 1046 LP - 1052 DO - 10.1124/jpet.103.059337 VL - 308 IS - 3 AU - Laine J. Murphey AU - Wendy K. Eccles AU - Gordon H. Williams AU - Nancy J. Brown Y1 - 2004/03/01 UR - http://jpet.aspetjournals.org/content/308/3/1046.abstract N2 - We studied the effect of salt intake and hypertension on the systemic kallikrein-kinin system (KKS), as measured by bradykinin (BK) 1-5, a stable circulating bradykinin metabolite, and the tissue KKS, as measured by urinary kallikrein excretion. Venous BK 1-5, urinary kallikrein, and components of the renin-angiotensin-aldosterone system were measured in 35 normotensive and 19 hypertensive subjects who were maintained on a high (200 mmol/day) or low (10 mmol/day) salt diet. Salt restriction decreased mean arterial pressure (MAP) (P < 0.001 overall) and the plasma angiotensin-converting enzyme (P = 0.017) and increased plasma renin activity (P < 0.001) and serum aldosterone (P < 0.001). There was an interactive effect of salt intake and hypertension on plasma BK 1-5 (P = 0.043), with BK 1-5 significantly lower during low compared with high salt intake in normotensive (24.7 ± 2.6 versus 34.9 ± 5.6 fmol/ml, P = 0.002) but not hypertensive subjects (30.6 ± 4.6 versus 27.5 ± 2.8 fmol/ml, P = 0.335). In normotensives, the change in plasma BK 1-5 from high to low salt intake correlated with the change in MAP (r = 0.533, P = 0.004). Urinary kallikrein was higher during low compared with high salt intake (P < 0.001) in both groups. There was no effect of salt intake on urinary BK 1-5. In summary, the systemic and renal KKSs act in tandem to modulate the response to salt intake. The systemic system is activated during high salt intake and counterbalances increased vascular response to pressors. With sodium restriction, the renal system is activated and counterbalances the increased sodium-retaining state induced by activation of the renin-angiotensin-aldosterone system. With hypertension, these modulating effects are diminished or lost, supporting a role for both systems in the development/maintenance of hypertension. The American Society for Pharmacology and Experimental Therapeutics ER -