Notes: 3-Methylcrotonyl-L-carnitine-d3 is intended for use as an internal standard for the quantification of 3-methylcrotonyl-L-carnitine by GC- or LC-MS. 3-Methylcrotonyl-L-carnitine is a derivative of L-carnitine (Item No. 21489) and a leucine metabolite.{47174} Hepatic and plasma levels of 3-methylcrotonyl-carnitine are increased in mice with diabetes induced by streptozotocin (Item No. 13104).