[A 13-week subchronic toxicity study of D-xylose in F344 rats]

A 13-week subchronic toxicity study of D-xylose was performed in male and female F344 rats at dose levels of 0%, 0.2%, 0.6%, 1.7%, and 5% D-xylose in the CRF-1 powder diet to determine the maximum tolerable dose (MTD) for subsequent investigation of carcinogenicity. Rats were randomly allocated to 5 groups each consisting of 10 males and 10 females. Rats were randomly allocated to 5 groups each consisting of 10 males and 10 females. No treated groups showed changes in body weight gain or food intake, and all animals survived until the end of the experiment. Hematological examination revealed significant increases in RBC, Hb, and Ht in the male groups treated with 0.6% and 5% concentrations, whereas these values decreased significantly in all of the female groups treated with D-xylose. However, no clear dose-response effect was observed in the hematological data in either males or females given D-xylose. Serum biochemistry studies revealed decreases in AsT in the 0.2% and 5% D-xylose group male and 0.2%, 1.7%, and 5% group female, compared to the control value. However, the changes were not considered specific because of the lack of any clear dose-response effect. In addition, no histopathological changes indicating obvious toxicity of D-xylose were observed in the livers of either sex treated with D-xylose. Based on these data, the MTD of D-xylose in F344 rats of both sexes is judged to be 5% or more in the diet.