DL-threo PDMP is a mixture of ceramide analogs that contains two of the four possible stereoisomers of PDMP (Item No. 62595): D-threo-(1R,2R)-PDMP and L-threo-(1S,2S)-PDMP.{11392} DL-threo-PDMP inhibits glucosylceramide synthase by 33 and 48% in MDCK cell homogenates when used at concentrations of 5 and 10 µM.{11341} It reduces the synthesis of glucosylceramide, increases cellular ceramide, and induces cell cycle arrest in vitro.{11342} The ability to inhibit glucosylceramide synthase has been found to reside in the D-threo-(1R,2R) enantiomer.{11393} The D-threo-PDMP enantiomer is also responsible for inhibition of ?-1,4-galactosyltransferase 6 and prevention of lactosylceramide synthesis, which is a promotor of neuroinflammation in mice during chronic experimental autoimmune encephalomyelitis (EAE), a model of multiple sclerosis.{27728} DL-threo-PDMP increases amyloid-? (1-42) (A?42) and A?39 production independent of ceramide metabolism via modulation of ?-secretase activity in HEK293 cells expressing the ?-secretase substrate SC100.{36880} [Matreya, LLC. Catalog No. 1719]