Gangliosides of cultured cells of a rat mammary carcinoma cell line.

Ganglioside content of rat mammary carcinoma-derived cells grown in layers in vitro was nearly as high as that of apical membrane-derived milk fat globule membrane and nearly four time higher than the content of normal, lactating mammary tissue on a protein basis. The major ganglioside of these carcinoma-derived cells was identified as GDla (sialic acid-Gal-GalNAc-sialic acid)-Gal-Glc-Cer. Relative to carcinoma-derived cells, rat mammary tissue and milk fat globule membrane had more complex ganglioside patterns but appeared to lack substantial quantities of GDla.