Validity of Values for Glomerular Filtration Rate and Extracellular Fluid Obtained From Plasma Concentration-Time Decay Curves After Single Injections of Mannitol in the Dog

Abstract

The plasma concn. of mannitol decays with time after a single injn. in the dog in such a manner that the curve of concn. vs. time may be used to calculate GFR and extracellular fluid. In the past the use of this method with various substances has been disappointing, especially in man, because of mixing delay and extrarenal disposition of the test substance. These errors become negligible in the dog when mannitol is the substance used. To calculate the GFR the following formula was used: _M_ [ P2