C22 Galactosylceramide-d4 is intended for use as an internal standard for the quantification of C22 galactosylceramide (Item No. 9003458) by GC- or LC-MS. C22 Galactosylceramide is a sphingolipid that has been found in the central nervous system.{41138,46936} C22 Galactosylceramide levels are increased in the spinal cord, but not the brain or liver, of mice fed a methionine-restricted diet.{41138} C22 Galactosylceramide has been found in postmortem hippocampus from patients with Alzheimer's disease.{46936} As this product is derived from a natural source, there may be variations in the sphingoid backbone. [Matreya, LLC. 2214]