The First Evidence of the Formation of a Protein-Free Filtrate

Question

The first evidence of the formation of a protein-free filtrate was provided by
A) Renal titration curves
B) Micropuncture studies of the glomerular fluid
C) Microscopic investigation of nephron structure
D) Demonstration that the potential obeys Gibbs-Donnan equilibrium
E) Calculation of the double ratio

Accepted Answer

Micropuncture studies of the glomerular fluid provided the first evidence of the formation of a protein-free filtrate in the kidneys. This technique allowed researchers to directly sample and analyze the fluid in different parts of the nephron, including the glomerular filtrate, demonstrating its composition and the filtration process.