Angiotensin-1-Converting Enzyme Activity in the Spontaneously Hypertensive Rat

Abstract

Spontaneously hypertensive rats of the Okamoto Wistar strain have reduced angiotensin-1-converting enzyme activity in the serum, kidney and anterior pituitary (P < 0.01) as compared to control Wistar Kyoto rats. The activity of this enzyme in lung, testis, epididymis, posterior pituitary and hypothalamus did not differ between control and spontaneously hypertensive rats. Angiotensin-1-converting enzyme in the kidney of the control and the spontaneously hypertensive rats were immunologically identical. Mixing experiments showed that the depression of enzymatic activity in the kidney and the anterior pituitary could not be accounted for by the presence of an inhibitor in the extracts. The concentrations of angiotensin-1-converting enzyme evidently are altered from control levels in the spontaneously hypertensive rat regulation of this enzymatic activity may occur independently in different organs.