Analysis of Relationship Between Renin-Angiotensin System and Blood Pressure in Experimental Hypertension Induced by Kidney Extract

Kidney extract (I), (II) and (III) were obtained from rats which were adrenalectomized and given tap water, adrenalectomized and given 10 g/l NaCl, and intact, respectively. When each extract was subcutaneously injected every 12 hours into uninephrectomized rats, the blood pressure was gradually elevated. This hypertension-inducing action was observed more or less in every extracts. The potency was (I) > (II) > (III) while no apparent disparity was found in renin content of the three extracts. During and after the development of hypertension, plasma renin level was not increased 12 hours after the injection except in the recipients of extract (I), even in the presence of a high blood pressure. However, from an aspect of changes following each individual injection, the effect of the kidney extract on the plasma renin level appeared to be parallel with its hypertension-inducing effect. The latter effect, therefore, could be attributed to a cumulative effect of an excessive fluctuation of the renin-angiotensin level or the blood pressure, although implication of other renal substances than renin would not be excluded. Continuous high level of plasma renin or angiotensin may accelerate the development of hypertension.