Abstract

The kallikrein kinin system is a tissue-derived system with potent renal and cardiovascular effects. Within the kidney, the components of the kallikrein kinin system (kallikrein, kininogen, kinins, kininases, kinin receptors and mediators/modulators) originate from or are located in discrete segments of the nephron in highly specialized cells which determine its physiological effects. The kallikrein system acts on the kidney in a paracrine fashion in two anatomical microenvironments where the system regulates glomerular function, renal hemodynamics, and salt and water excretion. Impairment of the renal kallikrein system contributes to the development of hypertension, in particular to the salt-sensitive hypertension, and other pathologies like diabetes. There are several links between the vasodepressor kallikrein system and the vasopressor renin system which are relevant to normal renal function and to the pathophysiology of hypertension and renal diseases. Local induction of kininase II or angiotensin converting enzyme in the kidney could be a novel mechanism contributing to the renal damage in hypertension and other renal diseases. This review evaluates cellular and functional aspects of the renal kallikrein system with emphasis placed on the cellular localization of its components along the nephron, the links to other vasoactive systems, and the contribution of the system to the pathogenesis of hypertension.