Effects of changing salt and water balance on renal kallikrein, kininogen and kinin

Effects of changing salt and water balance on renal kallikrein, kininogen and kinin. The kallikrein–kininogen–kinin system (KKK) has been implicated in the renal sodium excretion response to changes in dietary sodium. However, both increases and decreases in the activity of this system have been observed when urinary sodium excretion is augmented by a variety of maneuvers. To further evaluate the potential physiologic role of this system, we measured three components of the KKK system in urine. Total kallikrein, intact kininogen, and kinin were measured twice in normal individuals during balance on both a high (250 mEq/day) or low (10 mEq/day) sodium intake. A consistent and significant reduction in the activity of all three components of the KKK system was noted during the high salt intake. Furthermore, during the high sodium intake, further acute reductions in components of this system were observed when an acute saline but not water load was administered. The consistent response of the various components of the KKK system to both acute and chronic sodium loading suggests that the system is physiologically linked to the regulation of sodium balance. However, the directional changes argue against a primary natriuretic effect of this system.