The renal kallikrein-kinin system at the prehypertensive stage of hypertension.

In essential hypertension, renal dopaminergic activity and PGE2 was suppressed as was the renal kallikrein-kinin system. The suppression of the renal depressor systems may play an important role in the etiology of hypertension through sodium and body fluid retention. At the prehypertensive stage of essential hypertension, renal dopaminergic activity was suppressed, which induced the retention of body fluids and sodium. On the other hand, the renal prostaglandin E2 was augmented, and it seemed to be a compensatory mechanism for sodium retention. We could not confirm the suppression of the renal kallikrein-kinin system at the prehypertensive stage of hypertension. Although all renal depressor systems are suppressed in essential hypertension, the suppression of the renal kallikrein-kinin system and PGE2 seem to be very important in the etiology of hypertension. Further study is necessary to clarify when both systems are suppressed.