Micropuncture: unlocking the secrets of renal function.

This article focuses on the development of micropuncture which is considered as one of the greatest advances in renal physiology during the 20th century. It was developed by J.T. Wearn and A.N. Richards who described the method for performing micropuncture in frogs. It was the first experimental evidence that a protein-free glomerular ultrafiltrate is separated from the bloodstream and the first evidence for tubular reabsorption. Wearn and Richards measured protein, glucose, chloride, potassium, urea and pH in blood,glomerular fluid and bladder urine. Comparison of the composition of blood to glomerular filtrate proved that a protein-free watery fluid is separated from the blood as it passes through the glomerulus.