indication

Historically used in an important medical test of renal function, specifically a measure of glomerular filtration rate. Sometimes used to help relieve symptoms of diabetes mellitus - a condition characterised by hyperglycemia and/or hyperinsulinemia.

pharmacology

The inulin test is a procedure by which the filtering capacity of the glomeruli (the main filtering structures of the kidney) is determined by measuring the rate at which inulin, the test substance, is cleared from blood plasma. Inulin is one of the more suitable and accurate substance to measure because it is a small, inert polysaccharide molecule that readily passes through the glomeruli. The inulin clearance test is performed by injecting inulin, waiting for it to be distributed, and then measuring plasma and urine inulin concentrations by various assays. As nutraceutical agents inulins may have antitumor, antimicrobial, hypolipidemic and hypoglycemic actions. They may also help to improve mineral absorption and balance and may have antiosteoporotic activity.

mechanism of action

As a diagnostic agent, inulin is readily soluble and essentially indigestible. It readily passes through the blood and into the urine. It is neither secreted nor resorbed by the kidney making it an excellent indicator for renal clearance rates. The inulin clearance test has largely been succeeded by the creatinine clearance test as a measure of glomerular filtration rate. As a hypoglycemic agent, inulin is not digestible by human enzymes ptyalin and amylase, which are designed to digest starch. As a result, inulin passes through much of the digestive system intact. It is only in the colon that bacteria metabolise inulin, with the release of significant quantities of carbon dioxide and/or methane. Because inulin is not broken down into simple sugars (monosaccharides) by normal digestion, it does not elevate blood sugar levels, hence, helping diabetics regulate blood sugar levels.

biotransformation

Metabolized into carbon dioxide and methane by colonic bacteria

absorption

Poorly absorbed, passes through to urine unmetabolized

half life

2-4 hours