RENAL RESPONSES TO SLIGHT ELEVATIONS OF RENAL ARTERIAL PLASMA ANGIOTENSIN II CONCENTRATION IN DOGS |
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Authors: | Robert H. Fagard Allen W. Cowley Jr L. Gabriel Navar Herbert G. Langford Arthur C. Guyton |
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Affiliation: | Departments of Medicine and Physiology and Biophysics, University of Mississippi School of Medicine, Jackson, Mississippi, U.S.A. |
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Abstract: | 1. Angiotensin II was infused into the renal artery of intact kidneys of slightly volume expanded anaesthetized dogs at rates of 125, 250, 500, and 1000 pg/kg body weight per min, resulting in elevations of the calculated renal arterial plasma angiotensin II concentration of 16·9 (s.e.m. = 2·1), 35·0 (s.e.m. = 4·3), 73·3 (s.e.m. = 8·8), and 159·8 (s.e.m. = 20·4) pg/ml. 2. Angiotensin II caused significant dose-dependent decreases of renal blood flow and of renal plasma flow of -4·1% (s.e.m. = 1·5, P(0·05) at the lowest and of -19·6% (s.e.m. = 1·4, P(0·001) at the highest rate of infusion. Glomerular filtration rate remained essentially unchanged at the two lower infusion levels and decreased by -6·7% (s.e.m. = 2·2, P(0·05) and -8·3% (s.e.m. = 2·5, P(0·05) at the higher rates of infusion. Filtration fraction thus increased by +6·3% (s.e.m. = 2·4, P(0·05) at the lowest and by +14·2% (s.e.m. = 3·6, P(0·01) at the highest rate of infusion. 3. Urine volume decreased by -7·7% (s.e.m. = 0·8, P(0·001) at the lowest and by -35·2% (s.e.m. = 4·8, P(0·001) at the highest rate of infusion, while the study showed similar dose-dependent decreases for urinary sodium and potassium excretion and for the fraction of filtered sodium excreted. |
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Keywords: | diuresis filtration fraction glomerular filtration rate kaliuresis natriuresis renal blood flow renal plasma flow renal resistance. |
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