Renal, Transcapillary, Net Exchange in the Dog

The transcapillary net exchanges of inulin, para-aminohippurate, thiocyanate and heavy water were determined in the renal circulation. It was found that the tracer substances larger than heavy water diffused more freely through renal than through previously studied peripheral or pulmonary capillaries. The results are consistent with the concept of a larger pore size in renal capillaries.