[The primary importance of the kidneys in the development of essential hypertension]

The participation of the kidneys in the development of renovascular and renoprivic hypertension has been known for a long time. The kidneys are, however, important also in the development of essential hypertension: these views are based on transplantation studies on various types of hypertensive and normotensive rats and their hybrids and transplantation studies in patients. In the genesis of hypertension participates the dual regulation of blood pressure by the kidneys: a) the renin-angiotensin-aldosterone system in the renal cortex which is manifested by two mechanisms (high- and low-renin hypertension resp.) with a number of functional and metabolic effects of angiotensins and aldosterone, b) the medullipine system with the production of medullipine I by interstitial cells in the renal medulla and its transformation into effective medullipine in the liver. The latter prevents the vasoconstrictor effect of pressor factors. Some other vasopressor and vasodilatating factors participate in the regulation of blood pressure by acting as mediators. These findings have not only a theoretical but also an immediate impact on evaluation of the prognosis and selection of treatment of essential hypertension.