Humoral factors in the pathogenesis of primary hypertension

In 42 spontaneously hypertensive rats of the Münster strain either parabiosis or cross circulation with normotensive Wistar Kyoto rats was performed. Cross circulation was made through the common carotid arteries and external jugular veins using a peristaltic pump. In parabiosis and in cross circulation experiments hypertension was transmitted from the spontaneously hypertensive rats to normotensive rats. Nephrectomy or adrenalectomy in the spontaneously hypertensive rat before cross circulation abolished this effect. After volume depletion in the hypertensive animals hypertension was not transmitted either. It is concluded that humoral factors causing vasoconstriction play an essential role in the development of hypertension in the spontaneously hypertensive rat.