Abstract
A number of observers have found that extracts from the kidneys of various animals may have pressor effects. 1 – 7 The object of the present investigation was to determine whether extracts of kidneys from human beings and dogs with hypertension had greater pressor effects than those of control kidneys.
Kidneys were obtained at autopsy from 15 patients with hypertension and from 17 control subjects. The hypertensive group consisted of 9 patients with benign hypertension, 2 with malignant hypertension, 2 with chronic glomerular nephritis, and 2 with pyelonephritis and secondary contracted kidneys. The material was put through a meat grinder, crushed in a mortar, shaken for 30 minutes with saline (one cc. per gm.), filtered and kept on ice. The tests were most satisfactorily performed on an unanesthetized dog with a Van Leersum (carotid) loop. 8 In several instances records were obtained by direct cannulation of the carotid artery of anesthetized dogs and cats. Injections were made intravenously, using the equivlent of 7 gm. of tissue for the unanesthetized dog and smaller doses for the anesthetized animals.
A single injection usually resulted in a transient depressor effect followed by a gradual and prolonged rise which lasted from 10 minutes to over 3 hours. The average rise in blood pressure in the hypertensive group was 28 mm. of mercury, the range being 9 to 60 mm. of mercury. The average pressor effect in the non-hypertensive series was 12 mm. of mercury, the range being 0 to 48 mm. of mercury.
The pressor action in general was more prolonged in the hypertensive than in the non-hypertensive group. No striking differences in the preliminary depressor effects were observed.
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