The effects of 5% and 25% galactose diets on lens polyols, glutathione and protein glycation in male and female pigs.

The cataractogenic effect of a galactose diet was studied in male and female pigs in relation to the daily galactose intake. Two experiments were performed. In the first, 10 male and 10 female pigs were maintained on a 5% galactose diet for 30 days; galactose was given either as pure sugar or as hydrolyzed whey. In the second experiment, 18 castrated male and 21 female pigs were fed a 25% galactose diet for 49 days. Galactose was given as whey, hydrolyzed whey or as an alternating diet. Lenses were analyzed for sugar-alcohols, glutathione and protein glycation, and compared to lenses of pigs on a control standard diet. The 5% galactose diet induced large accumulation of dulcitol in the lens, which was similar whether galactose was ingested alone or as hydrolyzed whey. Glutathione and inositol contents were slightly below control values only in males on the galactose alone diet, perhaps indicating initiation of a cataractogenic process. No change was observed in females. The lenses of females on control diet were different from those of control males: having decreased glutathione, inositol and sorbitol contents and higher protein glycation. The 25% galactose diet resulted in an approximately 10 times higher lens dulcitol accumulation and advanced lens damage as measured by loss of inositol and increase in protein glycation. These changes were more severe in males than in females. The data indicate that there is a relationship between total galactose intake and dulcitol accumulation.