Abstract
A previous publication 1 reported the occurrence of cataractous changes in the eyes of all rats fed on rations containing lactose as the chief source of carbohydrate. Negative results with other carbohydrates tested led to an investigation of galactose as the next logical step. This sugar was fed to young rats at 35% and 25% levels corresponding to the galactose available from the 70% and 50% lactose rations fed in previous experiments.
Four rats on the 35% galactose ration developed mature bilateral cataract in 12, 14, 14, and 37 days respectively (average 19 days), whereas those on the 25% galactose ration were somewhat more delayed. The average time for the development of mature bilateral cataract in 49 rats fed the 70% lactose ration was 10 weeks, approximately 4 times as long. Controls fed on the 70% starch ration showed no eye changes.
The rations used in the experiment are shown in Table I.
Growth was subnormal on both galactose and lactose rations but galactose caused no diarrhea, a consistent result from lactose feeding. Galactosuria was more severe on galactose than on lactose rations. The calcium content of cataractous eyes was of the same magnitude on the 2 sugars but the increase apparently took place in a shorter time in the rats fed galactose. The calcium content of all eyes showing mature cataract was 3 to 4 times that of eyes from older rats on the 70% starch ration.
A more complete and rapid absorption of galactose from the alimentary canal when the sugar was fed as such than when derived from hydrolytic cleavage, and a slow glycogenesis, may well account for the slightly high blood sugars and galactosuria noted in these rats.
Get full access to this article
View all access options for this article.