Renal tubular flow dynamics during angiotensin diuresis in the rat.
1. Tubular size and lissamine green transit times were measured in rat kidneys undergoing a diuretic response to angiotensin II (0.5 mug/kg per min), and compared with the changes observed during diuresis induced by osmotic diuretics, noradrenaline and chlorothiazide.2. Angiotensin always caused a marked prolongation in proximal and distal tubular transit times; individual distal convolutions were coloured for prolonged periods, and lissamine green appeared in high concentration in distal tubules.3. Marked changes were observed in superficial tubular calibre during a stable diuretic response to angiotensin. Where distal tubular diameter was normal for the rate of urine flow, proximal tubular volume was generally reduced. In a number of experiments, however, distal tubules were markedly dilated, and in these cases proximal tubular volume was also often increased. Angiotensin may therefore be capable of causing a degree of internal hydronephrosis in the rat kidney.4. Prolongation of dye transit times, and the appearance of a concentrated lissamine green bolus in distal tubules, was suggestive of a decreased superficial nephron flow rate, indicating that the diuretic effect of angiotensin may take place only through deeper nephrons.
D000804:Angiotensin II / Q000494:pharmacology*; D000818:Animals; D002740:Chlorothiazide / Q000494:pharmacology; D004396:Coloring Agents / Q000097:blood / Q000652:urine; D004231:Diuresis; D005947:Glucose / Q000494:pharmacology; D007444:Inulin / Q000032:analysis; D007671:Kidney Concentrating Ability / Q000187:drug effects; D007684:Kidney Tubules / Q000187:drug effects*; D007734:Kymography; D008353:Mannitol / Q000494:pharmacology; D009638:Norepinephrine / Q000494:pharmacology; D011188:Potassium / Q000032:analysis; D051381:Rats; D012964:Sodium / Q000032:analysis
D004396:Coloring Agents; D000804:Angiotensin II; D008353:Mannitol; D002740:Chlorothiazide; D007444:Inulin; D012964:Sodium; D005947:Glucose; D011188:Potassium; D009638:Norepinephrine