Zur Frage einer direkten Angiotensinwirkung auf die Natriumresorption im proximalen Tubulus und in der Henleschen Schleife der Rattenniere
✍ Scribed by M. Horster; W. Nagel; J. Schnermann; K. Thurau
- Publisher
- Springer
- Year
- 1966
- Tongue
- English
- Weight
- 687 KB
- Volume
- 292
- Category
- Article
- ISSN
- 0031-6768
No coin nor oath required. For personal study only.
✦ Synopsis
Micropuncture experiments on the rat kidney were performed to evaluate the effect of angiotensin upon tubular sodium reabsorption.
Half time reabsorption as measured by the split droplet method was constant (9.4 ~= 0.4 see) at glomerular filtration rates ranging from 0.66--1.26 ml/g kidney/ min, and remained unchanged when peritubular or tubular angiotensin concentration was elevated, indicating no direct effect of angiotensin upon transporting capacity of the proximal tubule for sodium.
Sodium reabsorption in Henle's loop was studied by means of perfusing single loops with isotonic saline. From the increase in inulin concentration in the perfusat and from the sodium concentration in the early distal segment sodium reabsorption along Henle's loop was calculated. The correlation between perfusion rate and sodium reabsorption was found to be the same in the control experiments and during the perfusion with saline containing angiotensin with concentration of 0.5 and 5.0 × 10 -s g/100 ml.
These results together with the findings that urine volume and sodium excretion in the anaesthetized rat remain unchanged during the i.v. infusion of angiotensin indicate that angiotensin has no direct effect upon tubular transporting capacity for sodium.
Changes in tubular sodium reabsorption due to angiotensin, as calculated from clearance data, are considered to be the effect of an indirect action of angiotensin upon tubular sodium reabsorption.
Viele Befunde weisen darauf hin, daI~ das Oetapeptid Angiotensin in die l%egulation des Elektrolyt-Wasserhaushaltes eingeschaltet ist, wobei jedoch seine Funktion in dieser Regulation bis heute nieht eindeutig gekliirt ist. Neben der a]lgemein anerkannten v~somotorisehen Wirksamkeit des Angiotensins [22] bestehen abweiehende Ansichten fiber seine Wirkung auf die tubul/ire Resorption des Natriums. DAvis [7] vertritt