Increased production of angiotensin II in the adrenal gland of stroke-prone spontaneously hypertensive rats with malignant hypertension.

Angiotensin(Ang) contents in the adrenal gland of stroke-prone spontaneously hypertensive rats(SHRSP) and age-matched Wistar Kyoto rats(WKY) were determined using reverse phase high performance liquid chromatography combined with a specific radioimmunoassay. In normotensive 5 wk-old SHRSP, the adrenal renin activity was about 3 times higher than that of age-matched WKY while the adrenal Ang I and Ang II concentrations did not differ from those of WKY. In the severely hypertensive 25 wk-old SHRSP, the adrenal Ang II and Ang I, and plasma aldosterone concentrations were about 5-fold, 2-fold and 4-fold, respectively, increased compared with levels in the WKY. In the 25 wk-old SHRSP 24 h after bilateral nephrectomy, the adrenal Ang II and plasma aldosterone levels were not decreased and were 10 and 3 times, respectively, higher than those of nephrectomized control WKY. Thus, the enhanced local generation of Ang II in the adrenal gland may contribute to the increased release of aldosterone in SHRSP with malignant hypertension.