Microinjections de sodium et d’inuline marqués dans les capillaires du rein de Hamster

Publisher Website
Google Scholar
Abstract
A solution containing both labelled sodium and inulin was given by microinjections into the superficial peritubular capillaries of the renal cortex of hamsters undergoing saline diuresis. In the 15 experiments performed, the excretion of radio Na in the ureteral urine was considerably less than simultaneous excretion of inulin. In the 11 studies in which urine was collected from both ureters, the quantity of radio Na excreted was approximately equal on both sides and the curves relating excretion rate and time were essentially the same. The urinary recover of the 2 indicators permits the conclusion that excretion was determined by the levels of the 2 indicators in the systemic circulation. Thus, after the injection of radio Na of high specific activity into capillaries in close contact with proximal and distal convoluted tubules, there was no evidence of any important direct diffusion of Na from the capillary blood into the tubule fluid. In contrast to the results obtained by others, the present studies, in which direct manipulation of the tubules was avoided, demonstrate that the convoluted portions of the nephrons possess a low passive permeability to Na, in the direction opposite to that of active transport.