Para-aminohippuric acid

Para-aminohippuric acid (PAH) is a compound used in physiology to measure renal plasma flow, the rate at which plasma is delivered to the kidneys. PAH is filtered in the glomerulus and is also secreted into the proximal tubule to be excreted in the urine. This allows for the calculation of renal plasma flow, which is an important measure of kidney function.

History

PAH was first synthesized in the early 20th century and has been used in physiological studies since the 1930s. It was initially used to study the function of the kidney, and later to measure renal plasma flow.

Physiology

PAH is used in the measurement of renal plasma flow because it is both filtered in the glomerulus and secreted into the proximal tubule. This means that almost all of the PAH that reaches the kidneys is excreted in the urine, allowing for the calculation of renal plasma flow.

Clinical use

In clinical settings, PAH is used to measure renal plasma flow as a way to assess kidney function. This can be useful in diagnosing and monitoring conditions such as chronic kidney disease and acute kidney injury.

Pharmacology

PAH is administered intravenously and is excreted by the kidneys. It is not metabolized by the body, which makes it an ideal substance for measuring renal plasma flow.

See also

• Renal physiology
• Renal function
• Glomerular filtration rate