1977 年 41 巻 6 号 p. 665-675
The hypotensive effect of 1-Sar-8-Ile-angiotensin II, a competitive antagonist of angiotensin II, and the pre-infusion level of plasma renin concentration were examined in conscious rats with various types of hypertension to assess the role of the renin-angiotensin system in the pathogenesis of experimental hypertension. The infusion of 1-Sar-8-Ile-A II (0.64 μg/min or 3.2 μg/min) caused a significant fall in blood pressure in two-kidney Goldblatt rate (4-5 weeks after clipping) and 7-8-month-old stroke-prone spontaneously hypertensive rats (SHR), while it was statistically ineffective in one-kidney Goldblatt rats (4-5 weeks after clipping), one- and two-kidney Loomis rats (2 and 4-5 weeks after induction), 5-month-old stroke-prone SHR and 2-, 5-, 8- and 14-month-old stroke-resistant SHR. A significant correlation between plasma renin concentration and the susceptibility to the antagonist was observed in Goldblatt rats and stroke-prone SHR, but not in Loomis rats and stroke-resistant SHR. Some groups of animals which had not responded to the original infusion of 1-Sar-8-Ole-A II were infused again with the same antagonist in a furosemide-induced volume-depleted state, in which plasma renin level was prominently elevated in all rats and angiotensin-II dependency of blood pressure was disclosed except in the 8-month-old stroke-resistant SHR. These data suggest that the renin-angiotensin system is critically involved in the two-kidney Goldblatt rats and the 7-8-month-old stroke-prone SHR, but that it is much less important in other hypertensive rats and other factors would be involved especially in case of stroke-resistant SHR.
