Disposition of exogenous tritium-labelled GM1lactone in the rat

The disposition of labelled [3H]GM1lactone, the inner ester of ganglioside GM1, was studied in the rat. After i.v. administration [3H]GM1lactone was quickly converted to its corresponding open form most likely by plasma esterases, and then displayed a pharmacokinetic profile identical to [3H]GM1. Following intramuscular administration of [3H]GM1lactone [3H]GM1 levels in plasma and in tissues were higher than those obtained after the administration of an equivalent dose of [3H]GM1. This increased bioavailability means that GM1lactone can be considered as a potential prodrug of GM1.