The kidney, similar to the heart, plays a three-fold role in essential hypertension. First, it participates in the patho genesis of arterial hypertension. Second, it suffers as a target organ of long-standing hypertension, and third, it experiences the effects of antihypertensive therapy. Perhaps most contested at the present time is the involvement of the kidney in the patho genesis of essential hypertension. More than a century ago, William Osler put forward three basic hypotheses about the "genuine contracted kidney. "l 1. "The hypertrophy can be regarded as an effect to overcome a sort of...