Gangliosides in normal and cataractous lenses of several species

The present study was undertaken to compare the content, composition and distribution of gangliosides in ocular lenses of different species, both normal and cataractous. Gangliosides were extracted from cow, pig, rat and human lens by either the Folch-Suzuki partition procedure or by the modified tetrahydrofuran procedure. Between 20 and 45% more ganglioside was recovered from lenses by the tetrahydrofuran than the Folch-Susuki partition procedure. Cow, pig, rat and human normal lens extracted by the tetrahydrofuran procedure contained, respectively, 24.8, 22.3, 71.2, and 272.5 micrograms of ganglioside sialic acid/g lens (wet wt.). No protein-bound sialic acid was detected in any lens. No significant differences were observed in the content or composition of gangliosides from normal and cataractous human lens and from cataractous rat lens induced by the drug U18666A. Although hematoside (GM3) was the predominant ganglioside in bovine (73%) and pig (68%) lens, small amounts of what appeared to be GM1, GD1a, and GT1 were also detected. GM1 predominated (95%) in rat lens, with the remainder being GM3. This is apparently the highest relative content of GM1 reported in a non-neural tissue. Human lens contains two gangliosides, GM1 (53%) and GM3 (47%). Examination of the distribution of gangliosides between various regions of the bovine lens revealed that the epithelial cell fraction contained an about 10 times higher concentration of total gangliosides than either the lens cortex or nucleus.