Preparation and characterisation of tritiated derivates of galactosylceramide and glucosylceramide

Radiolabelled glucosylceramide and galactosylceramide have been prepared by the catalytic tritiation of a mixture of the corresponding unlabelled sphingolipids, and purified by preparative thin‐layer chromatography. The localisation of the label was determined by degrading the individual monohexosyl ceramides with aqueous methanolic hydrochloric acid and measuring the radioactivity content of the liberated fragments. Under the particular experimental conditions described, more than 98% of incorporated tritium was found in the ceramide portion of each sphingolipid, while the greater part (> 80%) of this radioactivity was detected in the long‐chain fatty acid moieties. The method offers a convenient means of preparing labelled substrates suitable foruse in metabolic studies. The data suggest that to reduce costs, mixtures rather than individual sphingolipids, can be tritiated.