Effect of a renin-system inhibitor on blood-vessel adaptation in spontaneously hypertensive rats.
We tested the hypothesis that a metabolic error may be the triggering mechanism which leads to blood-vessel hypertrophy and hypertension. Young spontaneously hypertensive rats (SHR) were fed a moderately high salt diet to exacerbate the purported metabolic error. Haematocrit values and rubidium transport were measured as evidence of renal ATP deficiency and blood-vessel adaptation. The renin system was inhibited in two groups of SHR by giving them enalapril to determine whether angiotensin II was involved in blood-vessel adaptation. Spontaneously hypertensive rats fed the moderately high salt diet had higher haematocrit values than normotensive rats fed the same diet or SHR fed Purina rat food, suggesting a renal ATP deficiency. Spontaneously hypertensive rats had higher Na+,K+-ATPase activity in thoracic aorta after 60 min incubation than a similar group given enalapril (P less than 0.001), suggesting blood-vessel adaptation. Possibly, angiotensin II within the vasa vasorum stimulates hypertrophy which, according to the Folkow hypothesis, leads to higher blood pressure, but may concomitantly increase the respiratory chain units which provide ATP for renal function and ion transport.
Gould
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Department of Medicine, Hahnemann University, Philadelphia, PA 19102.
Goodman
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SA
D000804:Angiotensin II / Q000378:metabolism; D000806:Angiotensin-Converting Enzyme Inhibitors / Q000494:pharmacology*; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D001808:Blood Vessels / Q000187:drug effects* / Q000503:physiopathology; D001835:Body Weight; D004656:Enalapril / Q000494:pharmacology; D006400:Hematocrit; D006973:Hypertension / Q000378:metabolism* / Q000503:physiopathology; D008297:Male; D051381:Rats; D011918:Rats, Inbred SHR; D011921:Rats, Inbred WKY; D012083:Renin / Q000032:analysis; D012413:Rubidium / Q000378:metabolism
D000806:Angiotensin-Converting Enzyme Inhibitors; D000804:Angiotensin II; D004656:Enalapril; D012083:Renin; D012413:Rubidium