THE IMPORTANCE OF THE KIDNEY IN PRIMARY HYPERTENSION - INSIGHTS FROM CROSS-TRANSPLANTATION

Experimental renal cross-transplantation studies with genetically hype rtensive and normotensive rats have shown that hypertension travels wi th the kidney. The underlying mechanisms are currently not well unders tood. Genetically normotensive recipients of a kidney from spontaneous ly hypertensive rats show a decreased capacity to excrete sodium when challenged with a high-salt diet. Furthermore, they retain more sodium than recipients of a kidney from genetically normotensive donors imme diately after transplantation and removal of the native kidneys. Sodiu m retention precedes hypertension and may contribute to its developmen t. Most recently, it has been shown that bilateral nephrectomy and tra nsplantation of a genetically normotensive kidney attenuates the devel opment of hypertension in young transplanted spontaneously hypertensiv e rats. Thus, long-term blood pressure in renal transplanted rats is c ritically determined by the genetic background of the renal graft. Tog ether, these data indicate that genetically determined renal mechanism s play a major role in primary hypertension.